Book - Biomicroscopy of the eye 2-25
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Berliner ML. Biomicroscopy of the Eye - Slit lamp microscopy of the living eye II (1949) Paul B. Hoeber, Inc. Medical Book Department Of Harper & Brothers, New York.
|24 Developmental Lens Changes.
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25 Presenile and Senile Cataract
Progressive Lens Opacities (Cataract) in Children, Young Adults, and the Aged
One should like to call some of these "adolescent cataracts,â€ but since thejâ€™- appear at times in very young children when they conceivabl)'^ might be congenital or later in adult life when they may be associated with frankly presenile or senile lens changes, it is difficult to name or group them according to any chronologic pattern. For example, most writers have classified them all under the heading of "presenile and senile opacities.â€ In my opinion the inclusion of such opacities as coronary, cerulean, and dilacerated under the heading of presenile and senile, as has been done by most authors, is confusing despite, the fact that some of these opacities may first appear in adult life. The use of the terms "presenileâ€ and "senile,â€ like that of "adult nucleus,â€ tends to give the impression of later development than is actually the case. Starting with those preferably found in the young and eventually including all the changes which seem to be forerunners of senile cataract, and finally senile cataract itself, the following cataractous formations are listed:
I. Coronary, cerulean, and dilacerated opacities
2. Water (slits) clefts; spokes
3. Lamellary dissociation or separation
4. Peripheral cuneiform cataract
y Various presenile and senile punctate opacities
6. Senile peripheral concentric lamellar opacities
7. Axial punctate opacities - sutures of anterior cortex
8. Immature cortical cataract (intumescent cataract)
BIOMICROSCOPY OF THE EYE
9. Mature cataract
10. Hypermature cataract
11. Crevice formation (in mature and hypermature cataract)
12. Anterior saucer (cupuliform) cataract
13. Posterior saucer (cupuliform) cataract
14 . Senile nuclear cataract
15. Nuclear cataract with double focus
16. . Cataracta brunescens et nigra
17. Rarer forms of senile lens changes
18. Capsular opacities and folds
With age, the lens undergoes certain physical and chemical changes. It becomes relatively flatter, and the older central fibers gradually are compressed by the continual growth of the outer cortical fibers. The progressive sclerosing process within the lens (especially of the nuclei) is manifested at the end of the fifth decade by the loss of accommodation or molding effect secondary to diminution of elasticity of the capsule."' Biomicroscopically the only definite indication of these changes may be evinced as a generalized increase in relucency. The adult nuclear relief is particularly well observed in senescence. However, it is not exactly known whether this highly reflecting zone actually limits the surface of the hard nucleus, which is commonly expressed at the time of an extracapsular cataract operation. At the same time, the capsule tends to thicken and to lose elasticity with advancing years while the epithelium itself, as has been shown histologically, following the rule of senescent epithelium all over the body, involutes. It may be that some of the capsular changes (shrinkage and wrinkling processes) are demonstrated by the increasing visibility of the shagreen, alread}^^ seen in young adult life, and by the rarer phenomenon, usually seen later, senile exfoliation of the zonular lamella. Duke-Elder states that "the changes in the sclerosed lens correspond to those of ageing tissues generally - a gradual dehydration with a loss of the water binding capacity, a diminished metabolism, an accumula
According to Vogtâ€™s idea, this would mean that the axial part of the fibers no longer are able to thicken.
PRESENILE AND SENILE CATARACT 1093
tion of waste material, with the deposition of sterol and calcium deposits, a decrease in permeability, and a rearrangement of the mineral skeleton of the tissues.â€ These are the physicochemical manifestations of lens senility, inherently and genetically determined, as are all the changes of senescence governed by species, individual, and even organ determinants.
The complicated question arises, if, when, and how much are the changes of senescence influenced by the so-called "exogenousâ€ influences, such as toxins arising from fatigue; radiant energy; endocrine d3'^scrasias; nutritional deficiencies; and infections (see discussion on diabetic cataract, p. 1177). Also, how much of a role do these play, for example, in the presenile lens changes? Are they the result of an inherent abiotrophy (premature senility), some of which so closely resemble cataractous changes seen in the frank endocrine cataracts? These questions are as ^'^et unanswerable but at the same time certain definite morphologic patterns do occur in presenile and senile cataract (as well as in congenital cataract) in regard to types and specific localization of the changes. Vogt with considerable evidence has made a strong plea for heredity, suggesting that not only the lens as a whole, but even groups or sections of fibers (e.g., cortex or nucleus) have individual specific genetic determinants which when faulty could lead to dissolution or weakness. In this way also, outside influences (environmental) could secondarily precipitate cataractous changes easily. Vogt has shown, especially in his studies of identical twins, that the appearance of such changes are chronologically as well as morphologically similar in spite of difference of environment. The finality of such a conception, although true within limits, if carried to the extreme, could easily result in a state of defeatism - a condition not unlike that existing in the eras of antiquity and the middle ages when investigators were satisfied with authoritarian systems of identification and classification only. As it now stands, we must await the physicochemical advances of the future because it may be shown that what some investigators now consider inexorable laws of nature may be in the end controllable.
BIOMICROSCOPY OF THE EYE
It will be seen that Vogt does not clearly separate presenile lens opacities from those that are definitely known to form senile cataracts. For example, in cases in which presenile opacities (coronary)
Fig. 389. Diagram showing the principal tjâ€™pes of opacification of the lens. A. Frontal view. B. Optic section; p marks the border of the dilated pupil. Above, opacities, chiefly club-shaped, of a coronary cataract; below, senile cuneiform opacities. In A, to the right, lamellar separation. In B. in the middle, nuclear cataract involving only the fetal nucleus and leaving free a little central inten'al.
are found in the second and third decade, water slits, lamellary separation, and spokes frequently will form so that after a time an eventual cortical cataract develops. This association or gradual transition of these forms is not uncommon. However, it should be pointed out that certain of these so-called "ptesenileâ€ opacities are observed in the young and, as such, may be confused with congenital cataracts. Most of them are found outside of the region of the inner fetal nucleus and their Y-sutures or in between the central coffee beanlike nuclei and the stripe of the adult nucleus and in the cortex. The deeper part of the so-called "adultâ€ nucleus is already present at birth and separates the capsule from the inner fetal nuclei. In addition, except for cataracta dilacerata and some isolated small flat opacities, the presenile opacities, particularly those found in the 3 mung, are chiefly peripheral (e-g., coronary and cerulean cataracts) . It is interesting to note that nuclear cataract begins in the fetal parts of the lens (Fig. 3 ^ 9 )'
PRESENILE AND SENILE CATARACT
Coronary Cataract (Cataracta Coronaria; Cerulean Cataract; Cataracta Cerulla [Blue]
ET ViRiDis [Green])
The biomicroscope demonstrates easily that this is one of the most common forms of presenile cataract but because of its peripheral location behind the iris it may be overlooked unless the pupil is dilated widely. According to Vogt (confirmed by G jessing and others cataracts coronaria et cerulea are found in at least 25 per cent of all persons after puberty and are hereditary. Usually bilateral, they may appear to be stationary but over long periods of time, most of them progress slightl)'^ to a varying degree. This is seen in cases observed over a long period of time. In the early stages the opacities are isolated or few in number but later they tend to develop into a continuous wreath. As a rule, by themselves they do not disturb central vision unless associated with other types of lens change, especiall) senile cataractous alterations. Coronary cataract begins in the periphery, occupying that portion of the lens corresponding to the border between the middle and outer third of the lens radius, appearing very much like a crown or wreath situated on the equator of the adult nuclear zone. Frequently the opacification extends within the adult nuclear stripe or external to it within the deeper cortex. The surfaces of the opacities form a thin layer concentric to that of the adult nucleus and according to Vogt extend onion-like. This corresponds to the direction of the concentric lamellae (page 1010) seen so distinctly in macerated preparations and which, according to him, are not related to the radial lamellae of Rabl. The shape of the opacities vary (clubs, disks, lines and rings) but the most prominent are club-shaped. The thickened sharply outlined, rounded parts of the clubs extend in an axial direction reminiscent of dentate stalactites. Peripherally the tapered processes of the clubs may extend posteriorly around the equator of the adult nucleus or may terminate at the equator in a diffuse manner (Plate LXVI) . Frontally finer radiating linear or spiral opacities â€™ Weissenbach, i9i7;C^4 Krenger, Horlacher, 1918 Kirby,
Fig. I. Coronary cataract. Diffuse illumination.
Fig. 2. Same case as shown in Figure i. Direct focal illumination.
Fig. 3. Coronary and cerulean cataract. The central opacities exhibited a vivid color display. Note signs of cortical changes. (Water clefts and lamellary separation) . Diffuse illumination.
Fig. 4. Same as case in Figure 3. Direct focal illumination.
Fig. 5. Coronary and cerulean opacities showing peripheral clubs and smaller rounded forms axially. Diffuse illumination.
Fig. 6 . Same as case shown in Figure 5. Direct focal illumination. Fligh power.
PRESENILE AND SENILE CATARACT 1099
are frequently seen. The linear appearance springs from the fact that observation is directed at the edges of the opacity tangentially as they extend around the equator. In some cases the clubbed opacities may be so close to one another as to seemingly fuse. The color of these opacities varies according to their density. Thin forms may appear grayish with a faint bluish tint while the well-developed ones are whitish. No exact explanation for the formation of these clubs has yet been given, but Vogt has suggested that perhaps it is related to the expansion of fluid between the concentric lamellae of the lens. In a case of traumatic cataract, he has seen that vacuoles (shaped like clubs) can lead to opacification. If the vacuole is located peripheral!)'â€™, it becomes a club-shaped opacity, and if it is more axial, it assumes a discoid or ring shape.
In addition to the characteristic clublike formations, more axially located discoid or ring forms may be found. They begin as very thin grayish or bluish nebulous opacities in the deeper cortex, and are only visible by direct focal light. Later when these roundish opacities tend to become more opaque and white they may be observed by retro-illumination.'^â€™ They may extend centrally but because of their transparency do not usually affect vision. However, exceptions occur in which, owing to increasing density, these opacities, when axially located, may interfere with vision. Frequently irregular groups of dotlike opacities may be seen between the disks and rings. Another typical form of opacity, usuall)'- associated with the clubs are the linear concentric opacities. They appear as broken
The color variations seen in these opacities probably depend on their screening action of incident light. As in blue iiides the coloration manifested by the semitransparent whitish iris tissue when viewed against the dark background of the posterior surface is a consequence of the diffusion of incident light so the cerulean opacity gains its color as it is viewed against the dark pupillary background. Depending upon the degree of light diffusion within the opacity (nitra lamp) a greenish hue may be imparted (cataracta viridis). Frequently retroilluminated light from the deeper portions of the lens (mirror reflex) may give anteriorly located opacities a brownish hue. The thicker opacities appear white in direct focal illumination. However, the fact that coronary and cerulean disk- and ring-shaped opacities may show various spectral colorations (from bright red to violet) has caused many to question the origin of this phenomenon. As an analogy Vogt cites the work of Ehrenhaft (1914) and of Gerde Laski (1917) which indicates that the color of small colloidal molecules depends upon their size. In this way the smallest appears violet while the largest appears red. Intermediary ones would be green or blue. This hypothesis of color dispersion was also referred to earlier by Hess (ipii).'^'^Â® According to Bellows, Hessâ€™ explanation is based on the observation of Lord Rayleigh who found that in an opalescent medium containing innumerable particles of a different refractive index, the dispersion of light is inversely proportional to the fourth power of its wave length.
BIOMICROSCOPY OF THE EYE
or dashlike concentric lines running at right angles to the direction of the clubs and are situated in the extreme periphery. To see them it is often necessary to employ a wide angle of observation and illumination, comparable to that used when looking at the periphery of the fundus with the ophthalmoscope. The direction of these short concentric lines is not unlike the longer and perhaps slightly more axially located stripes in the deep cortex in cuneiform cataract. As a matter of fact, coronary opacities (especially in adult life) may be associated with the latter as well as many other types of presenile opacities (e.g., dilacerated forms). The formation of water slits leading to spokes (which appear thin in sagittal section) in cases of coronary cataract is a concomitant senescent finding. Vogt stated that this combination is hereditary and is one of the most frequent of all presenile lens changes, and that after one learns to recognize these characteristic thin spokes, which often extend into the axial region, the presence of a coronary cataract may be predicted, even before dilating the pupil.
Cerulean cataract is often found together with coronary opacities. The former, however, is distinguished by the presence of discoid, ringlike or irregularly shaped opacities, colored blue or green and limited to the adult nuclear region. This type of cataract, which undoubtedly is a subform of coronary cataract, is found in younger individuals (Plate LX VI, fig. 5). Consequently in some instances it may represent a congenital form. In other cases the opacities may be situated on the surface of the adult nucleus, so it is difficult to make any definite statement regarding their true time of origin. Cerulean opacities have even been identified in hypermature cataracts (Vogt) . The fact that the blue color is retained in spite of the white background is an exception to the previous explanation of the color changes. However, in these instances, the presence of a layer of less relucent fluid may contribute to color formation.
This type of colored opacity may be seen rarely in the inner fetal nucleus, so that at times a peripheral coronary cataract may be associated with central opacities of the type seen in cerulean cataract.
These spokelike or coronary opacities may be very thin and frequently show coloration
PRESENILE AND SENILE CATARACT
Coronary and cerulean opacities may also occur concomitantly with many of the developmental cataracts referred to before, e.g., stellate, anterior, axial, embryonal cataract, etc. The direction and location of the smaller bluish dotlike, or at times irregular or spiral threadlike opacities varj'^ from case to case. In the periphery they may form concentric layers, while those situated more centrally may be arranged radially. Despite the circumscribed opacities found within the nucleus it is usually less relucent than the cortex, giving the impression of a dark area surrounded by a hazy cortex. The short spiral radial lines, which were mentioned before as located at the equator between the clubs, can also be found more axially. Vogt gives their average size as from 0.12 to 0.2 mm. long and 20 p thick. Their direction and shape seem to correspond to that of the wavy sclerosed nuclear fibers. They may appear brownish or grayish in color.
Although coronary cataracts are generally considered to form at the time of puberty, the fact that analogous forms of thin colordisplaying spots may be found in the deeper nuclei, and that they are bilateral and familial in occurrence, leads to the conclusion that these slightly progressive forms are all related and are genetically determined.
DILACERATED CATARACT (vOGT) (cATARACTA DILACERATA
This type of opacity, first described by Vogt in 1921 is found frequently in association with coronary, cerulean, and centrally located congenital cataracts. Morphologically it resembles a small fiat piece of teased-out moss or sponge with frayed edges (Fig. 390) . Similar to the linear coronary opacity of the periphery, the opacities tend to extend along a lamella in a concentric direction (Fig. 375 B, C). The fact that opacities do extend in this way seems to substantiate the idea that the lens is composed of concentric lamellae as well as radially directed fibers. The color of dilacerated opacities IS usually gray. However, occasional whiter-looking strands may be
BIOMICROSCOPY OF THE EYE
seen. Also like coronary and cerulean opacities a dilacerated opacity may reveal a yellow, blue or green coloration.
In an individual lens these opacities may appear singly or multiple.
Fig. 390. Dilacerated cataract.
Dilacerated cataracts may be within the adult nucleus but not necessarily in the axial regions. In one case, in a man who had bilateral coronary cataracts I saw four of these thin grayish opacities, in one eye only, arranged circularly just below the surface of the adult nucleus. They were located in an area corresponding to the middle third of the lens radius. One of them had a definite leaflike ribbed internal structure. The main part of the opacities was composed of fine irregular threads and dots. The immediate area surrounding it was hazy, gradually fading into the background. Vogt said that he was unable to determine at what age dilacerated cataracts developed, but that they were probably congenital or acquired early in life. It is not known whether these opacities are stationary or progressive.
Under this heading we shall first consider the progressive types of presenile and senile change that morphologically seem to be the underlying basis of or at least an integral part of the lesion known clinically as "senile cataract.â€ Because these changes (e.g., punctate dots, water slits, spokes, lamellary separation,â€ cuneiform opacities, and nuclear opacification) may appear early in adult life and may
PRESENILE AND SENILE CATARACT 1103
span decades before they seriously interfere with vision, they have been classified as presenile. But rapid extension of some of these processes at any time may result in the appearance of a mature senile
Fig. 391. Mature senile cataract. Frontal view showing large radial water slits.
cataract within a very short period. Before the days of biomicroscopy such changes, when sufficiently advanced to produce opacities visible with the loupe or ophthalmoscope, were classified according to their location as cortical, nuclear, and posterior lamellar cataracts; and according to their development (and incidentally their effect on vision) as early or incipient, intumescent, mature, shrinking or hypermature, and morgagnian or liquefied cortical cataracts. Nuclear cataracts were classified as early or well-developed with subdivisions such as central hyperrefringens (for lens with double focus [Koby] ) and cataracta brunescens and nigra when accompanied by color changes. However, even though biomicroscopy has advanced our knowledge concerning the morphologic development of these opacities, at the present time it has warranted no change in the older clinical classifications or terminology.
It is a common daily experience to find cases in which all types of changes (cortical, nuclear, and posterior saucer) are simulta
BIOMICROSCOPY OF THE EYE
neously present. W^ith the narrow beam, even in these cases the separate lesions can be distinguished except, of course, when the cortex is coagulated and opaque. As already discussed, the cortex is composed of younger fibers and is located just below the capsule; it reacts morphologically in a different way than the nucleus, the fibers of which are older and more compressed. These differences are apparently due to physiologic sclerosis of the nucleus.'-' This process is protective since it retards rapid or intense opacification thereby conserving vision for a longer time. The water binding power of the lens varies with age so that with increasing â€œsclerosisâ€ the water content increases. We are unaware of this process biomicroscopically until proteolytic enzymes causes disintegration and consequent opacification. In discussing the chronologic progression of the presenile and senile changes leading eventually to the clinical forms of senile cataract, Vogt tends to disregard the local metabolic and physicochemical influence preferring the genetic theory. He considered these alterations so far as rate of development and time of inception is concerned as being comparable to those seen in other tissues, e.g., senile atrophy of the pupillary margin, arcus senilis, graying of the hair, etc. Vogt stated that he could prove that more than 90 per cent of persons over 60 years of age have senile opacities of the lens varying individually in the same way as senile changes in other organs. Moreover, if the question is asked why all lenses do not become completely opaque with age, then the same question must be asked concerning time of appearance of other senile changes.
From this standpoint the difference in behavior of the cortex and the nucleus is manifested by the greater ease with which the sutures and fibers of the cortex become separated by fluid, eventually resulting in an intense opacification (precipitation of lens protein ?) . The extreme is seen in morgagnian cataract in which complete dissolution and liquefaction of the cortex occurs. The nucleus seems to react less violently than the cortex. It simply becomes more or less uniformly cloudy.
An excellent summary of present day knowledge of the composition and metabolism of the lens is given by Bellows.^Â®^
t Since in some cases these changes develop rapidly within a few months and in others are stationary' for years.
PRESENILE AND SENILE CATARACT
In the cortex especially, the biomicroscope permits visualization from the very beginning of gross changes that apparently are associated with the imbibition of water, and the degeneration of the lens fibers. The earliest manifestations of these cortical alterations are the formation of water clefts (slits), lamellary separation, and groups of punctate opacities, probably similar or related to punctate opacities of the central cortical sutures. The opacification attending these processes go to make up the so-called incipient cataractous alterations of the cortex. Clouding of the fibers of the walls and contents of water slits results in "spokeâ€ formation. Separation of the concentric lamellae leads to peripheral cuneiform (pyramidal) opacities. Further extension of all these processes results not only in progressive opacification but also in swelling or intumescence."' Maturity is marked by almost complete opacification of the cortex. From this point on, owing to dialysis of water and disintegrated lens substance, regressive changes (hypermaturity) follow, characterized by shrinking. The rate of progress of these changes varies greatly, sometimes extending over years, with alternating periods of arrest and progression; in others cessation of development may occur at an early stage, resulting in an arrested form of incipient cataract. Loss of vision in these cases, particularly in the aged, may rather result from nuclear clouding than from cortical changes. On the other hand the progression to maturity of cortical changes may proceed with astonishing rapidity.
WATER CLEFTS (sLITS) AND SPOKES
Water clefts, a manifestation of the absorption of water by the cortex, are characterized by the appearance of dark spaces (of lesser optical density) in the form of (i) radially directed sagittal slits,
Bellows, citing Krauseâ€™s (1934)Â®^Â® hypothesis on the fluid trafficâ€ in cataract, states: "Following injury to the lens, acidosis results which stimulates certain proteolytic enzymes to act upon the lens substance. The fragmentation of the lens protein yields many smaller particles, increasing appreciably the osmotic pressure within the capsule. Water is accordingly attracted into the lens and the lens swells. In a rapidly forming cataract the end products of these hydrolytic processes accumulate, and marked swelling results. As the action of the enzymes continues, the protein residues are broken down to crystalloid size and diffâ€™use out of the lens.â€
Fig. r. Water clefts in the anterior cortex. Direct focal illumination.
Fig. 2. Water clefts in the posterior adult nucleus (girl, i6 yrs.). Direct focal illumination.
Fig. 3. Spoke formation as seen by retro-illumination.
Fig. 4. Deposits of myelin droplets within a spoke, as seen by retro-illumination. Fig. 5. Droplets seen in light reflected from the fundus.
Fig. 6. Lamellary separation associated with pyramidal or cuneiform opacities. Fig. 7. High-power view. Direct focal illumination. Optic section showing details of a water cleft and laminary separation.
PRKSl-NILl- AND SENILU CATARACT
corresponding to tlic sutures or (2) in larger lamella-like separations (corresponding to the concentric lamella) which extend sheetlike frontally. Water slits may form also as a result of separation of fiber bundles. This type has also been noted in traumatic cataract and in massage cataracts. In the latter cases, particularly in the aged, massage of the anterior lens capsule without rupturing the capsule, can cause a localized disruption of lens fibers. Spokes, so commonly seen in the periphery of the cortex, are water slits with partial or total opaque contents.
Earlier authors (preblomicroscopic) described radial slits and spokes and surmised that they were fluid spaces but it was Vogt (1919-31) who showed their connection to the sutures and who also demonstrated the larger fluid spaces caused by separation of the concentric lamellae. According to him, the latter confirms the idea that the lens is made up of layers of fibers which are concentric as well as radial.
Radial water slits may be seen in a more or less hazy way, frontally (especially in intumcscent cataracts) by oblique or diffuse illumination and the peripheral ones, i.e., those associated with spoke formation, can be seen opthalmoscopicallj'â€™ as clear spaces between spokes provided the pupil is dilated. Owing to retroreflected light from the deeper portions of the lens, water slits ma}â€™' appear blurred especially when employing the wide biomicroscopic beam. In order to see water slits clearly, especially in cross-section, the narrow beam is essential (Plate LXVII, figs. I, 2, 7). This is particularly true for water slits of the posterior cortical layers, where owing to diffuse reflection from the anterior portions of the lens, they can only be seen with the optic section (Fig. 392), With this method the appearance of the radial slits is striking. Dark, irregular, but sharply defined areas are seen outlined within the gray lens substance. Slight lateral movements of the beam will give "serialâ€ sections through the slit and usually disclose its irregular shape and extent. The distinctness of Water slits and of lamellar separations increases as the zones of specular reflection are approached. Sudden narrowings of the lumen of the slits are common as are sharp changes in direction. This at
BIOMICROSCOPY OF THE EYE
times tends to give the water slit a jagged appearance (Plate LXVII, fig. i). The irregularity of the walls causes them to have sharp splinter-like processes which protrude into the lumen of the slit.
This jagged appearance may be caused by the separation and breaking up of fiber bundles. In other words, instead of flat radial spaces separating the sutures (as seen frontally by diffuse illumination) the optic section will disclose that the water slits have a definite sagittal thickness which may extend irregularly through the width of the cortex from the surface of the adult nucleus to the line of disjunction. In only very rare instances do they project through the line of disjunction to reach the capsule."' Their common location is in the middle and deeper parts of the cortex. Likewise it is extremely rare to find a water slit within the adult nucleus, although I did see several in a single case of tramuatic intumescent cataract in a 1 6-year-old girl in which the slits seemed to extend into the adult nucleus. In the frontal view as well as in optic section it will often be noticed that slits result from dilations or separations of portions of the sutures and, corresponding to their direction, radiate from the axis. The ends of the slit are usually pointed toward the intact part of the suture and often empty into it. At times one slit runs into another at the place of branching of the suture or a clear slit may empty peripherally into an opaque slit (spoke). In addition delicate white fibrils, concentrically directed, may frequently bridge across a dark tunnelled-out water slit (Plate LXVII, fig. 7) . These are more commonly seen than radially directed bridges. Vogt believes that this proves a stronger continuity in radial fibers than in those concentrically directed. Macerated preparations show that the bind
According to Vogt, directly subcapsular slits are very rare and similar to other subcapsular opacities (e. g., saucer cataract) indicate a poor prognosis; since in such cases opacification progresses quickly. Degeneration just beneath the capsule shows that the youngest lens fibers are partaking in the process.
Fig. 392. Water slit seen by optic section. Subcapsular vacuoles. Vacuoles on the surface of the adult nucleus. Peripheral spoke in cortex below.
PRESENILE AND SENILE CATARACT
ing together of lens fibers in the direction of Rablâ€™s lamellae is more solid than those of the concentric zones. By diffuse illumination it will be generally noticed that the areas (walls) contiguous to the direction of the slit arc more relucent in certain places. This opacification has been explained as being brought about by the imbibition of fluid by the fibers nearest to the water slit. As a result the borders of the slit may appear partially as a narrow whitish line or even as radiating broader bands. In some cases this increase of reflection may be seen in optic section as outlining the jagged irregular edges of the slit. Since such opacification is seen commonly in intumescent cataract (water slits are an underlying process of intumescent cataract, whether senile, toxic, or traumatic) , it may be an indication of rapid progression.
Becker noted that dark water slits may appear opaque on change in direction of the incident light. This appearance is probably caused by regular (specular) reflection, not unlike the whitish color of the shagreen of the capsule seen in normal lenses. The shagreen itself when viewed over a water slit appears darker than otherwise even when the cleft is located deep in the cortex. This unexpected phenomenon may be caused, as suggested by Vogt, from lack of reflection of the subcapsular concentric layers unless they are interrupted by the formation of a water slit. Ordinarily brightness of the shagreen is augmented by diffuse and regular reflections from these layers. Butler, basing his contention on the point that he could see a capsule shagreen in morgagnian cataract (when the cortical fibers beneath the capsule were liquefied) believed that the shagreen results from specular reflection of the hyaline capsule alone. Von Hess concluded that the darkening of the shagreen in front of the clear water slits proves that the location of the latter is just below the capsule.
Using superimposed glass slides Vogt demonstrated experimentally the reason for the darkening of the shagreen over a water slit; he also demonstrated the optical illusion whereby in diffuse illumination they appear to be more superficial than is actually the case and the reason for apparent opacification of clear slits seen on alternating
1112 BIOMICROSCOPY OF THE EYE
the direction of illumination and observation. The fact that water slits are difficult to see at times and readjustment of the angle between observation and illumination is required, demonstrates, according to
Fig. 393. Vogt's arrangement of glass slides to illustrate optical phenomena of layers of cortex.
Vogt, that their refractive index differs little from that of the cortical substance. This is also the reason for the weak reflection of their walls. Their dull asbestos-like relucency becomes visible only by a certain angulation of the beamâ€™s direction. The index of refraction of the dark water slits is comparable to that of the corneal epithelium, the aqueous, or the fluid parts of the vitreous. Consequently Vogt reasoned that the fluid within the slits is derived from the aqueous and that this fluid differs from that of vacuoles. The latter have a different index of refraction, and hence are more easi y seen because of their vivid glitter; in addition they are more readi y visible in retro-illumination than are clear water slits. According to recent investigations, vacuoles consist of "myelinâ€ droplets, a degenerative product derived from the substance of the lens fibers;
.Vogt arranged a series of glass slides 393). one ^ the other
the layers of the cortex, ^he middle onÂ« ^
which might be compared to a of a water slit The whole arrange in order to imitate the irregu ar direction of the kark gap. A film of
ment was then placed on a dark backgroun s ^ niake^t uneven and to simulate a shavaseline was applied to the upper surface O surface, the dark
green field. If light of low intensity is permitted to O'O".
gap L is still seen in spite of it. The reflection be under the
Also as a consequence of refraction ^ suffers an apparent dislocation
surface 00 ' In other words as a result of retraction me gap toward 00 '.
toward the surface. With a wider angle Â°^Â®*^'Â®TÂ®hon it appears^
Such a shifting in vivo could easily result in an mc^^^ ^ allowed to be reflected
water slit might be thought to he su â€œPÂ® â€¢ O'O" This could explain why clear
PRESENILE AND SENILE CATARACT
biochemically myelin (a bi-ref ringent substance related to cholesterol) is insoluble in water or alcohol.
Investigating the frequenc)'â€™ of water slits, Pfeiffer in Vogtâ€™s clinic found that in 84 persons over 50 years of age their incidence was about 36 per cent and that they were twice as frequent in the anterior cortex as in the posterior. Koby states that "clear clefts appear after 50 years of age and it seems a little earlier in women than in men.â€ Kirby reported the presence of water slits and lamellary separation, alone or together, in about 12 per cent of 945 cataracts. Vogt has stressed the frequency of water slits in association with progressive coronary opacities in individuals between 30 and 60 years of age. In many of these cases the progress was extremely slow extending over decades and in spite of spoke formation vision may be only slightly affected if at all. In addition in some of these cases he was able to observe the hereditary nature of these coronary spokelike cataracts. According to Duverger and Veeth in 10 per cent of all cases seen, water clefts were observed in the absence of cataract or without cataract developing later.
Spokes. The opacification of radial water slits results in the formation of spokes which probably are one of the most common forms of lens opacities (Fig. 391) . This is a further extension of the process which in some cases proceeds slowly over decades and in others (when associated with extensive lamellary degeneration, fluid imbibition, and eventually individual fiber decomposition) leads to intumescent cataract. It is not unusual to find cases in which a few peripheral spokes develop and upon the formation of a nuclear cataract, the degeneration in the cortex is arrested, so that ultimately the loss of vision is due more to changes in the nucleus than to those in the cortex. Nuclear cataract in these cases would almost appear to inhibit the advance of cortical changes. Although we would like to think that only the central parts of the lens (adult and fetal nucleus) are subjected to sclerosis with age, evidently to a lesser degree this hardening can occur in the older parts of the cortex. When this happens it could easily inhibit the progression of spokes.
The opacification of the radial water slits with resultant spoke
BIOMICROSCOPY OF THE EYE
formation is a consequence of the deposition of myelin. This substance apparently is not soluble but rather forms a cloudy emulsion within the slit. This process is also seen to occur more rapidly in
Fig. 394. A. Spoke by retro-illumination, b. Spoke with myelin droplets viewed by light
reflected from the fundus. High power.
intumescent cataracts where not only the sutures and lamellae are separated by fluid and myelin but finally also the individual lens fibers themselves. Such a reaction can be reproduced within a day or so in macerated preparations.â€™** Ordinarily the conversion of a clear water slit into an opaque spoke may take several years. With higher powers, myelin droplets appear as whitish opaque bodies but by retro-illumination their vacuolar nature becomes apparent (Fig. 394 A, B) . Clear water slits cannot be seen, but vacuoles (subcapsular or within water slits) have a yellowish tinge, especially if viewed in the light reflected from the posterior mirror reflex (Plate LXVII, figs. 3,4). Depending on the direction of the light the edges nearest the light will glow (unreversed illumination) . (See Vol. I, page 90.) In addition, lens vacuoles, similar to those in the cornea, will project shadows deeper when viewed by direct focal light. Depending on the refractive index of the vacuole, as compared to
' In these preparations, a freshly removed lens is subjected to the maceration effects of a watery solution. Upon removal of the capsule sectors of lens can be easily separated by splitting of the sutures. In this way not only can the hydration changes comparable to senile changes be observed in the lens but also the concentric laminations of the sectors.
PRHSKNILE AND SENILE CATARACT
that of its surroundings, tlircc refractile phenomena may occur (Koby) : (i) If tlic refractive index of the contents is greater than that of the surrounding media, it acts like a convergent lens, producing a luminous cone bordered by two dark shadowy bands. (2) If the refractive index of the contents is less than that of the media, a divergent lens action results. This leads to a projected shadow of the vacuole encircled by a more or less divergent luminous beam. (3) When the refractive index of the body is the same as that of the media, a direct shadow formation occurs. (See Vol. I, Fig. 105.)
In light reflected from the fundus the myelin vacuoles within the spoke appear red (page 981). (Sec also. Fig. 394 B; Plate LXVI, fig. j.) As opacification of the contents of the water slits progresses the walls become increasingly opaque, evidently due to deposits of myelin in or between the adjoining fibers, possibly combined with pressure effects. The opacification of the walls in a radial direction causes the appearance of spokes or riders so commonly seen in the peripheral parts of the cortex ophthalmoscopically. However, some of them may result from cuneiform opacities (see below) . In direct focal light the age of a spoke is determined by its color. Old spokes are distinguished by their vivid opaque whiteness.
Several authors, Stanka,'^â€™'â€™ Galla, Klainguti and Vogt, have demonstrated after iridectomy that movement of vacuoles and other cortical opacities occurs with accommodative effort. Opacities move axialward during accommodation and then return to their original peripheral location during rest. Vogt believes that this represents proof of the intracapsular mechanism of accommodation (page 1016). He showed this in a case of hypermature cataract in which radially directed opaque fibers bent during accommodation and resumed their original shape on rest.
Lamellavy Separation (dissociatio lamellosa) is characterized by the presence of more or less parallel lines in the visible and deep cortex. They are generally found in connection with a sagittal separation (evidenced by dark spaces) of the so-called cortical concentric layers (Plate LXVII, fig. 7) . This is a second type of water slit. Like the radial water slit, it is intimately associated with cata
BIOMICROSCOPY OF THE EYE
ractous change of the cortex; it is also seen in macerated preparations. Time of appearance and rate of progression varies greatly from case to case. Whereas the formation of radial water slits repre
Fig. 395. Lamellary separation, frontal view. Nasally, the separated fibers are seen passing
over a cuneiform opacity.
sents the changes governed morphologically by the radial direction of the lens structures, lamellary separation is the expression of the same changes of the so-called concentrically directed layers (Vogt). Just as spokes develop from the opacification of the radial water slits, so do the peripheral cuneiform opacities arise from opacifications of the concentrically separated lamellae. (Fig. 395). There are still a great many unsolved problems concerning the nature of lamellary separation.
Owing to hydration, great pressure strains are created within the lens. This serves to separate along the lines of least resistance and according to their direction the various components of the lens structure. Evidently the sutures (radial) and the so-called concentric lamellae first show the effect of this stress, not unlike the opening of the seams in a leaky boat. Despite the fact that the lens fibers (Rabl) in equatorial section form radially directed lamellae, macerated preparations show a tendency toward concentric separation (see Fig. 367, p. ion). The latter, although not actually representing the true morphologic direction of the lens structure, evidently indicates that strains can cause separations in this direction. It is
PRESENILE AND SENILE CATARACT
difficult to explain this phenomenon except by the theory that fibers of the same age, being chemically similar and under strain, can separate sagittally and in a frontal way and as a result give the im
Fig. 396 A. Form of J.imcll.iry scp.ir.ilion. Parallel lines of sep.ir.ition extending across the lens without regard to suture sy'-tem. 11. Parallel lines of lamellary separation extending across tlie lens in front of cuneiform opacities.
pression that the lens is made up of concentric layers. In other words, here we are confronted by the fact that separations can occur ("across the grainâ€) which do not apparently correspond to the normal directions of the radially directed layers. In 1912 Vogt saw these lines in the deep cortex and at first thought that they represented fine folds (Fig. 396). These parallel lines can be seen in their full extent at the level of the nuclear relief by somewhat diffuse illumination when the pupil is dilated. It was found that they are more commonly located in the lower nasal sector. Predominantly, their line of direction is steep, starting from below temporally and running upward nasally. Simultaneously when this direction of lines occurs, cuneiform opacities will frequently be found nasally and below (Fig. 395) . Since these lines and intervening gaps may extend m other directions, Vogt pointed out that it is more proper, strictly speaking, to call them gap formations in the direction of the fibers rather than the concentric formation of gaps. It is difficult to understand why in some cases, in otherwise clear lenses, parallel lines of separation extend across the lens (from one edge of the pupil to the other) without regard to the suture s^'^stem (Fig. 396 A, B) . In these cases there is no interruption or change in direction as they pass
BIOMICROSCOPY OF THE EYE
over the sutures. While these lines usually seem to extend between the radial sutures, at times they are interrupted and appear like the cross threads of a spiderâ€™s web (Fig. 397) . The visibility of these
Fig. 397. Lameilary separation. Separated lamellae between sutures resemble the crossing fibers of a spiderâ€™s web. (Plastic model after Vogt.)
structures varies with their direction and the angle between observation and illumination; like the radial water slits they are best seen when the zones of specular reflection are approached. By slowly changing the angle of illumination the lines appear more or less distinct. In addition if the direction of the lines suddenly changes or differs from that seen with one position of the light, a change in the angle of illumination is necessary in order again to make them visible. In cataracta cuneiformis, white concentric lines of reflection are found in the region of the flat opacities themselves or just axially to them (Fig. 395). They run in a direction that is at right angles to the apices of the spearlike cuneiform opacities and may be located in front of or behind them.
In addition to those that extend frontally in apparently a single layer, the optic section frequently reveals the sagittal extension of small white lines through the cortex. Here, it will be seen that groups of short whitish parallel lines separated by dark intervening spaces traverse the cortex in a horizontal or oblique manner (Fig. 39^)
PRESENILE AND SENILE CATARACT
The exact explanation of these sagittally directed lines, which commonly cross concentrically directed water slits is not known. They may represent the opacification of radial lamellae which are sectioned
I â€¢ I
h d C
Fig. 398. Cortical cataract (incipient) as seen by direct focal illumination (wide beam). Pigment on the anterior lens capsule casts shadows. Water slits (dilated suture lines at the level of the surface of the adult nucleus). Note obliquely running white lines of lamellary separation, a, b, c, d, surface of the lens (broad beam [parallelepiped]); b, d, f, h, surface of adult nucleus; R, iris pigment deposits; Cb, shagreen of anterior lens capsule; f-b, deeper edge of parallelepiped or surface of adult nucleus; K, opaque adult nucleus; Su, dark suture on the surface of opaque adult nucleus; L, white lines (lamellary separation) located between capsule and nucleus; IF, border of water cleft; S, dark spots (to the left) representing shadows cast from the pigment deposits on the anterior lens capsule when viewed by light (retroillumination) from the deeper parts of the lens; N, surface of the adult nucleus. (After Vogt.)
by the narrow beam in their radial extension, in other words, lamellary separation of the radial lamellae. The dark gaps between the white lines may represent either the less relucent fluid which has separated and compressed lamellae, or groups of fibers similar to that which occurs in sutures in the formation of radial water slits. The direction of these lines like the longer ones, seen frontally and described above, in most instances tends to run obliquely from tern
BIOMICROSCOPy OF THE EYE
porally below to nasally upward. In one of Vogtâ€™s cases the white lines crossing a frontally directed water slit had a flared (?) and wavy appearance similar to those seen in diffuse illumination of the
Fig 399. Lamellary separation showing the bending of the lamellae as an expression of the
shrinking of the nucleus in the aged.
adult nucleus relief. He explains the bending of the lamellae as an expression of shrinking of the nucleus in the aged (Fig. 399) . Owing to the diffuse reflection from the anterior parts of the lens, lamellary separation of the posterior cortex is difficult to see. Vogt states that it does occur and when present the direction of the lines is predominantly opposite to the anterior cortex, namely from below nasally to above temporally.
The optic section often reveals that these whitish sagittally directed lines of separation are related to flat and frontally directed concentric water slits. It has been shown that in many instances this type of water slit is nothing more than the axial extension of the flat cuneiform opacities. The flattened cuneiform opacities are formed by myelin droplets in the walls of concentric water slits, in the same way that spokes develop from radial water slits. The sagittally directed lines mentioned above do not necessarily have to cross the entire cortical thickness but being short may only just extend across the front or back wall of the concentric slit. At times, particularly
PRESENILE AND SENILE CATARACT 1121
in intumescent cataract, small groups of vertically parallel white lines (lamellary separation) may be seen in various parts of the cortex without any apparent connection with the frontally directed water slits. However, it should be mentioned that these slits are often very difficult to see, requiring not only the employment of the narrow beam but constant readjustment of the angle between illumination and observation.
Schild in Vogtâ€™s Institute examined the eyes of 218 old persons. Lamellary separation was not found before the fiftieth year (although Vogt himself saw it in younger persons) . He found evidences of it in 7 per cent of persons between 50 and 60 years; 18 per cent between 60 and 70 years; 52 per cent between 70 and 80 years and in 50 per cent over 80 years of age. The direction of the lines of laminary separation was predominantly from temporally below to nasally upward. The spider-web form was infrequent (Fig.' 397) . In 75 per cent it was found to be bilateral and apparently was rarer in the posterior cortex.
CUNEIFORM CATARACT (CATARACTA CUNEIFORMIS PLANA
Cuneiform opacities constitute the most common form of cortical alteration confined to the periphery and as such play an integral part in the formation of senile cortical cataract. Characteristically they form flattened opacities (sagittally thin) , which like coronary cataracts may extend posteriorly around the equator to involve the posterior cortex (Fig. 400). Their peripheral edge usually runs parallel to the equator while their axially directed ends form broadly rounded, pointed or dentate processes. Although located in about the same depth of the cortex as coronary opacities, the flat pointed, angulated cuneiform opacities differ in appearance from the more rounded discrete clublike processes of coronary cataract (Plate LXVII, fig. 6) . It should be borne in mind also that coronary cataracts develop at an earlier age. Cuneiform opacities, like the lines of lamellary separation with which they are usually associated, are
BIOMICROSCOPY OF THE EYE
localized mostly in the lower nasal periphery, another difference from the coronary opacities, which are found circumferentially around the equator of the adult nucleus. Fusion of the axial dentate
Fig. 400. Unusual type of cuneiform opacities. (After Vogt.)
cuneiform extensions may result in broader segmental opacities (Fig- 395 ) Frequently concentric stripings are seen running at right angle just axially to the flattened cuneiform opacities. The innnermost part of these concentric lines often blend into laminary separations. Cuneiform opacities, like most of the other presenile or incipient cortical changes, tend to progress with time but with the usual unpredictable and individual variability. Axial progress is particularly noticeable posteriorly.
The concentric stripings may also run directly over the opacities themselves and probably indicate the close relationship between cuneiform cataract and the concentric lines of separation. Not infrequently cuneiform opacities are combined with flat (sagittally directed) water slits and radial spokes. The optic section will demonstrate the relative thinness of the opacities but despite this they
PRESENILE AND SENILE CATARACT
appear white in color by focal light. Retro-illumination especially of those in the posterior cortex will reveal a yellowish to brownish tinge (because of the yellowish color of the deeper parts of the lens in age). According to Vogt, the frontally flattened direction of cuneiform opacities and their relation to laminary separation supports the conception that the lens is composed of concentric (onionlike) lamellae. He holds that cuneiform cataract develops from the frontally flattened concentric water slits formed by the accumulation of fluid between the concentric lamellae. Opacification of this type of water slit (similar to the radial slits where opaque spokes are formed) results in cuneiform opacities. Moreover, as long as the slit is not opaque, we get the picture of laminary separation, a consequence of the separation of fiber lamellae by fluid. Cuneiform opacities are commonly bilateral and, similar to other presenile changes, may be genetically determined.
PRESENILE AND SENILE PUNCTATE OPACITIES ( CORTICAL)
Biomicroscopically, it is rare to find an adult lens without an occasional small, white, punctate dot in the cortex. They are so delicate that they cannot be observed with the loupe or with the ophthalmoscope. As such, they have been considered as physiologic but since they tend to increase with age and at times even interfere with vision, they have been properly classified under presenile lens opacities. These dots or small lines are especially prevalent in peripheral coronary cataracts. With advancing age they increase in number, especially in the equatorial region of the cortex (Fig. 368) . They are seldom found in the axial regions. At times in the aged they may fill the peripheral cortex appearing as dense snowflake opacities or as a fine dust. Occasionally, instead of being isolated or disseminated irregularly through the cortex, they may develop into linear stripes, deep in the equatorial region of the cortex, and following the nuclear curve, form booklets not unlike those seen in zonular and coronary cataract. As a matter of fact cases have been seen in which coronary cataract apparently developed from, or at least was
BIOMICROSCOPY OF THE EYE
preceded by, the presence of fine punctate dots peripherally. Small dot- or dustiike opacities are often associated with the various forms of senile cataract (cortical, nuclear, or cupuliform) as well.
Fig. 401. Concentric lamellar opacities (cuneiform type) extending around the adult nucleus
equator. Optic section.
SENILE PERIPHERAL CONCENTRIC LAMELLAR OPACITIES (VOGT)
When the diffuse dustiike opacities mentioned above, increase in number toward the equator, they may become condensed into concentric lamellae. They may form several layers separated by clear lens substance and when in the deeper cortex, extend parallel to the direction of the adult nuclear stripe (Fig. 401). The deeper ones may outline the nuclear equator as they round it to reach the corresponding layer posteriorly. It is necessary to employ the narrow beam in order to see the successive layers clearly. Since these opacities seldom reach the axial regions, they do not affect vision and are easily overlooked unless a mydriatic is used. Because of their location they may be confused with coronary opacities. In the early stages, with the pupil well dilated attention may first be called to such a change by the increased relucency of the adult nucleus near the equator in connection with the presence of small white dots. Concentric peripheral lamellar opacifications are usually found in association with other senile changes but not necessarily so. It has been found that the opacities vary from 0.8 to 1.2 mm. in width.
PRESENILE AND SENILE CATARACT
AXIAL PUNCTATE OPACITIES IN THE ANTERIOR CORTICAL
This is a characteristic type of opacity which, with lower powers of magnification, seems like a hazy delineation of the cortical sutures
Fig. 402. Axial punctate opacities in anterior cortical suture system.
(Fig. 40Z) . With higher power it will be seen that the haze is composed of minute dots, varying in color from gray to yellow, brown, or even reddish or coppery hues."' It is obvious that opacities of this kind, which are just barely visible with the biomicroscope, do not disturb vision in themselves; but since they occur in the older age groups, it is to be expected that they will be associated with the other changes of senescence. The latter (cortical and nuclear opacifications) which increase reflection posteriorly may add further difficulties in detection of the delicate punctate cortical suture opacities unless the narrow beam (optic section) and careful focusing are employed.
='â– ' Although apparently occupying the cortical sutures, this type of opacity is a stationary or very slowly advancing process. Vogt first saw such lesions in 1919 and states that probably because of their delicacy they were overlooked before this time. They are not connected with water slits or spoke formation because (i) there are no water slits in the vicinity of the affected sutures, (2) the microscopic dots are much smaller than any of those seen in water slits or spokes, and (3) the dots are of regular size with no tendency to coalesce into vacuoles. In addition, at times the tiny dots are colored and glitter like crystals. That this type of opacity is chiefly found in adults and the aged was shown by the compilations of Muller and RehsteinerÂ®^'â€™ who examined 267 institutional inmates. They found punctate anterior cortical suture opacities in 22 cases, or 12. i per cent. The ages varied from 40 to 90 years. In a group of 19 persons, aged 40 to 50 years, they found one case; while in a group of 70 persons, aged 61 to 80 years, they found 16 cases. Vogtâ€™s youngest case was aged 36 years.
BIOMICROSCOPY OF THE EYE
Starting in the axial region, the figure follows the design of the cortical suture system and branches out in radiating directions, gradually fading out in the outer one-third. Mostly the figure lies subcapsularly in the anterior parts of the cortex and only in one case did Vogt find it deeper, near the adult nucleus. He found that their length varies from 0.5 to 2 mm. and their width from 0.05 to 0.2 mm. However, all the suture branches of the system may not be affected. Sometimes the dots appear like glittering points. The reason for these color variations has not been explained, but it is similar to the hypothesis advanced for the color differences of cerulean opacities. Occasionally only a small group of dots (abortive form) may be present subcapsularly in the axial area of the suture or the point of fusion of the converging branches. In this case, of course, the radiating opacity will not have any branchings.
IRREGULAR CREVICES OR FISSURES IN THE ANTERIOR CORTEX IN MATURE AND HYPERMATURE CATARACT (VOGT)
Vogt described the finding of dark, irregular, more or less radial fissures in the anterior cortex of mature cataracts. They stand out sharply as dark cracks within the opaque cortical mass by contrast. At times the sharp edges of the fissures have a dentate appearance and, like a gear, appear to mesh with those of the opposite side (see Figs. 403 and 405A). These sharp-edged fissures differ from water slits in that they extend through the cortical thickness and probably result from shrinkage rather than from distention. Vogt stated that they reminded him of fissures formed in dry earth. Their radial direction may signify a relationship to the suture system. The width of the fissures vary from place to place. Frequently they have smaller terminal branches. In direct focal light, the passage of the beam into the depths may reflect a reddish color from the nucleus not unlike that of cataracta brunescens or nigra. Vogt also described similar dentate radial fissures within isolated lancet-like spokes of the anterior cortex. His impression was that these fissures originate in '.the cortex by retraction of its opaque substance and that it is not
PRESENILE AND SENILE CATARACT 1127
dependent on nuclear shrinkage per se. In any event, these ruptures are a late manifestation and differ in their genesis and time of appearance from the radial water slits, although the fissures may occur
Fig. 403. Intumescent to matuie cataract after paradichlorbenzine poisoning.
within them. Similar crevice-like formations have also been seen in total traumatic cataract.
IMMATURE CORTICAL CATARACT (INTUMESCENT CATARACT)
As a result of the progressive development of water slits, spokes, lamellary separation and cuneiform opacities, punctate dotlike opacities, etc. - all indications of hydration and subsequent dissolution of the lens fibers - the lens swells. Clinically the process of swelling may make itself manifest by a decrease in depth of the anterior chamber. The degree and rapidity of swelling or intumescence varies greatly depending on the intensity of the causative factors and the reaction of the lens to them. There are cases in which the stage of intumescence is short-lived, the cortex rapidly becoming completely opaque and the cataract mature. This is especially true in some types of toxic and traumatic cataract. In a case that I reported (paradichlorbenzine cataract) the changes proceeded with such rapidity that within a week the vision deteriorated from normal to the bare recognition of hand movements. Owing to the rapid swelling of the lens, which became entirely opaque in a few days, the
BIOMICROSCOPY OF THE EYE
intra-ocular pressure suddenly rose to such a high degree that on the seventh day following the inception of the cataractous changes, a linear extraction had to be performed (Fig. 403). The presence of sclerosis (nuclear) which may also effect the cortical fibers to a lesser degree, may act as a deterrent to intumescence. However it is not surprising that in younger persons, rapid swelling can occur in both the cortex and nucleus (Fig. 405 B). Although ordinarily the stage of intumescence is marked by an increase in water content as seen by the presence of numerous water slits and zones of lamellar separation in the beginning, opacification may be comparatively moderate, consisting of radial spokes and peripheral cuneiform opacities and dots, more or less limited to the deeper cortex (Fig. 398, p. 1119). As these changes progress, the cortex has a hazy appearance, when seen b)'- diffuse light. Grayish broad bands of opacity ma}^ converge from the periphery to the axial regions. The increase in whiteness of these spokes indicates their older age. These radiating band opacities may form rosette figures. At times the opaque spokes become fibrillated so that instead of being uniformly opaque, they appear to be composed of irregular branching radial white lines. Between these lines roundish opaque spots (opacified vacuoles) may be seen. Or the spokes, especially toward the periphery, may appear as homogeneous white lanceolate areas. In front of these dark or opaque spokes small subcapsular spots indicate the products of vacuolar degeneration.
Optic section will reveal large, often gaping, water slits surrounded by grayish zones (Fig. 404) . Groups of more or less parallel whitish lines running obliquely will be found in various places within the cortex. This type of laminary separation indicates that the fluid, which in the early stages resulted in the formation of clear water slits (radial and frontal), now has separated individual lens fibers and has caused them to become opaque (Fig. 398; Plate LXVII, fig. 7). It frequently happens that through manipulation (massage of the capsule with the iris repositor) either purposely or accidental!}'- during the performance of a preliminary iridectomy in cases in which nuclear cataract and only minimal cortical changes
Fig. 404. Intumescent cataract. Cortex shows large water slits. Note central disc-like capsular
Fig. 405. A. Intumescent to mature cataract. Note clearer subcapsular layer composed of vacuolar material. Viewed in optic section, b. Vacuolar type of cortical and nuclear cataract seen in a young person.
BIOMICROSCOPY OF THE EYE
exist, that a sudden intumescence results within a short time following the operation. The progression of the intumescent stages can then be easily observed - especially the formation of the broad opaque bands (opaque spokes) and of individual fiber opacification suggestive of the appearance of experimental maceration in vitro. Another interesting finding, even in the advanced stages of intumescent cataract, is the occasional presence of a relatively dark (clear) space between the main mass of cataractous cortex and the capsule (Fig. 405 A, B). In other words except for the tendency to vacuolar formation, the immediate subcapsular zone, which consists of the very younger fibers, tends to remain clear for a long time. This clear fluid-like space may be continuous with deeper radial water slits. At times in optic section near the main deeper mass of cortical opacities, one or more thin opaque layers of opacity may be found within the clearer subcapsular fluid layer. Vogt believes that such an independent layer represents the more solid continuity of fibers of a zone of discontinuity as compared to the intervening areas. The increase of curvature or bulging of the capsule can frequently be seen with the optic section. This method also reveals an actual increase of thickness of the cortex (Fig. 405 B). This can be verified by the fact that the anterior zone of specular reflection is smaller at any one given point than that found in a lens of normal capsular curvature. Because of an increase in curvature the number of specularly reflected rays from any one point will of necessity be smaller. This is exemplified in the normal lens in which, owing to the greater curvature of the posterior capsule, the shagreen area is always smaller than that of the flatter anterior capsule. Examination with focal light often reveals the association of pre-existing cuneiform and coronary opacities in the cortical periphery. However, it is still questionable whether the presence of coronary opacities influences or predisposes to the formation of the changes typical of senile cataract. I have in mind one case (Plate LXVI, fig. 5 ) , that of a 60year-old woman under my observation for at least fifteen years, who had especially marked bilateral cerulean and coronary opacities. At the present time her central vision is still 20/20 in each eye.
PRESENILE AND SENILE CATARACT
There are no other cortical presenile changes present but, as is to be expected, there is a slight increase in nuclear relucency. That similar changes to those of the anterior cortex occur in the posterior cortex during intumescence is undoubted. However, owing to accompanying anterior cortical changes, the inevitable nuclear cataract often present, and posterior saucer-like opacities (all resulting in increased internal reflections) examination of the posterior cortex becomes difficult during the intumescent, mature, and hypermature stages, but it is surprising how often examination of the deeper layers is feasible despite these changes.
RARER FORMS OF SENILE LENS CHANGES
Vogt has drawn attention to rarer forms of cortical senile cataractous changes that do not follow the ordinary patterns. Among these are the ring forms and disciform opacities found primarily in the axial regions. The former, found in the deeper cortex, consist of angulated opaque bands roughly forming a ring. Within and mixed with it there may be intensely white spots. The ring may be formed by opacification of the edges of the radial water slits in the axial region. Similar ring forms in the anterior cortex may occur in complicated cataract such as in myopia and glaucoma. The disk form is usually located in the deeper cortex. It may appear as a thin circumscribed opacity, composed of fine dots. In the case described by Vogt, the anterior surface of the disk was flat and the posterior surface was convex.
From the morphologic standpoint a cataract is considered to be mature when the opacification and disintegration of the cortex becomes complete, i.e., when the opacification actually or almost, reaches the capsule (Fig. 405 A) . Unless the central part of the lens has been involved by other types of opacities, vision may still be serviceable during the incipient and early intumescent stages of the cataract. But as maturity approaches vision becomes markedly reduced to a degree that the patient can barely count fingers or detect
BIOMICROSCOPY OF THE EYE
hand movements. Finally only the ability to perceive light is retained. The stage of maturity is marked by dehydration and by an increase in coagulation of the cortical substance. This loss of water is evidenced biomicroscopically by a reduction in swelling (flattening of the lens with increase of chamber depth) and by decrease in the size and number of the clear dark water slits. The chief feature is now an increase in opacification. The radiating bands (spokes) mentioned above become more intensely white, and, instead of being separated by clear fluid, it will be seen that they are crossed by opaque fibers or round or irregular opaque masses. The radial spokes themselves may become wavy or even broken up into smaller lanceolate opacities, so that very little, if any, indication of the original spokelike appearance remains. Larger, coarse vacuoles are not unusual (Fig. 405 A, B) . In direct focal light these may appear as dark or black holes within the opaque cortical substance, whereas their true vacuolar nature can be demonstrated by indirect or retroillumination. Carpets of subcapsular or perhaps epithelial vacuoles in direct focal light appear as delicate thin whitish opacities. Likewise with high power and indirect or retro-illumination it will be seen that these are composed of groups of very fine vacuoles. Vogt has described in great detail the various ways in which opaque fibers and darker lines may traverse spokes. In some cases delicate, more or less parallel white lines may cross a spoke at right angles to its radial direction. In others, dark lines corresponding to the dark spaces between individual opaque fibers may run radially in an irregular way, sometimes forming sinuous figures. He thinks that the former may represent a cross section of concentric lamellae, and that the latter represent changes in the radial lamellae. There is no reason to doubt that changes of maturity, similar to those that occur anteriorly, also occur in the posterior cortex. But, as pointed out in the section on intumescent cataracts, the latter are difficult to see except on the rare occasions when they have developed before nuclear and anterior cortical changes have precluded a clear view of this area.
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BIOMICROSCOPY OF THE EYE
Hypermature Cataract (Cataracta Hypermatura)
Hypermaturity of cataract in a gross way might be compared to the healing processes observed in other tissues. In the lens it is characterized by elimination of the degenerated lens products, in so far as diffusion of these substances via the lens capsule is possible, and by subsequent contraction and secondary organization of the cortical remains (Fig. 406) . The latter is illustrated by the frequency of calcareous deposits and crystals. Eventually this process leads to great shrinkage so that one may see a wrinkled capsule (at times unevenly curved owing to small concave depressions) containing a yellow nucleus, which is surrounded by degenerated cortical material. Consequently, there is a deepening of the anterior chamber. Just below the wrinkled capsule, numerous vacuoles may be found by indirect illumination (Fig. 407) . The nucleus may be displaced and, owing to degeneration of the zonule, the shrunken lens may become dislocated. In such cases iridonesis and phakodonesis may result. In extreme cases the lens may be converted into a thickened membrane or even, as has not infrequently been reported, a "spontaneous cureâ€ results since retraction of this membrane by the zonular filaments produces a veritable aphakia.
From the standpoint of biomicroscopy the chief initial indication of hypermaturity is the presence of capsular folds. The subcapsular cortex usually has a milky white appearance (beginning liquefaction), being composed of white clumped granular opacities. In a case recently observed, there were fairly small white flakelike particles (bilaterally) in the anterior chamber. At first it was thought that these were indications of an inflammatory process. There were no keratic precipitates. The irides were normal and the eyes were otherwise quiet. There was no peeling of the capsular lamellae visible, but one or two capsular folds were found. So far as could be seen no rupture in the capsules were noted. These flakes were observed unchanged for some months until the cataracts were operated on.
Apparent bending of the anterior capsule may result from an optical artefact following irregular astigmatism caused by corneal scars. When considering irregularities in capsular curvature one should not forget to eliminate corneal scars as a factor.
PRESENILE AND SENILE CATARACT
TJie recovery was prompt ajid eventful. . . . Evidently these particles were degenerated lens particles (capsular or cortical?) . The presence of such broken-down lens particles in the aqueous could in sensitized individuals set up an anaphylactic reaction and a toxic iritis.
Crysfah. The finding of glittering crystals is not unusual in mature and hypermature senile cataracts, as well as in complicated and traumatic cataracts. The) may occur as colored shining points or as long needles, presumably cholesterol (Plate LXVIII) . Such crystals can be found at times, especially in older persons in a relativel) clear sclerotic lens. But they also have been seen occasionally in otherwise normal lenses of children as a congenital condition. The direction of the needles may follow that of the radiating lamellae (especially at the periphery) where they may occupy spaces within the opaque cortex that correspond to the suture. In the axial region, however, groups of long varicolored glittering needles may traverse the deeper cortex and nucleus, apparently following no orderly pattern. At other times they may form leaves or layers. Smaller ones may be found (when lens transparency permits) near the embryonal Y-suture. Of themselves, like vitreous crystals, they do not interfere with vision.
Capsular Opacities. Another sign of maturity and hypermaturity, well known for a long time, is the presence of small capstdar opacifies. These may be the result of the opacification of hypertrophied capsular epithelium (Fig. 404). The spots in diffuse or focal light are grayish to white in color and generally are more or less circular. In one case the measurements of a comparatively large one was horizontally 0,56 mm. and vertically 0.4 mm. Like other capsular defects, which have a sudden level change at their borders, when observed in specular reflex these have a "shagreen free haloâ€ (page 974). When the opacity is observed in the mirror reflex, bright linear stripings will be seen frequently. Vogt has interpreted these as fiber formations brought about by epithelial proliferation. At times these stripes may glitter like crystals.
Complete liquefaction of the cortex results in the so-called "morgagnian cataractâ€ (Fig. 407). In these cases, which are compara
Fig. I. Crystalline (cholesterol) degeneration within the adult nucleus.
Fig. 2. Layer of fine crystalline deposits beneath the anterior lens capsule, corresponding to the anterior line of disjunction.
Fig. 3. Crystalline deposits in total cataract.
Fig. 4. High-power view showing the details of crystals seen in case in Figure 3.
PRESl-NILl- AND SENILE CATARACT
lively rare, the yellow sclerosed and opaque nucleus may be found almost floating within a fluid milky cortex or, owing to the effects of gravity, may sink somewhat within the saclike capsule. Vogt described three cases in elderly men having mature to hypermature cataracts in whom a sudden iritis with increased intraocular pressure appeared. The toxic iritis apparently results from the presence of cortical material in the anterior chamber. In all three cases the iritis and secondary glaucoma subsided after iridectomy, and was followed by a rapid shrinkage of the lens. The opaque nucleus sank, leaving a clear intact capsular sac above containing faintly relucent fluid with a few crumb-like pieces of opaque lens matter adherent to its inner walls. This kind of cortical shrinkage differs from that seen in hypermature cataract characterized by folds of the capsule, in that in the latter the capsule remains in close contact with the cortical remains and shrinks with it. In the former the capsule is separated from the shrunken cataractous mass and extends either tautly or relaxed in the direction of the zonular attachment. I recently saw a case in a 70-year-old man in whom the left eye had been operated on several years previously for removal of a cataract. There was a shrunken lens (hypermature) in the right eye. He suddenly developed pain and congestion in this eye, the pressure rising to 60 mm. (Schiotz) . After an iridectomy, the eye quieted down, and it was possible to see a clear capsular â€œbagâ€ in the coloboma. Some weeks later the shrunken lens was extracted intracapsularly with no complications, and eventually 20/40 vision was obtained. In the free part of the anterior capsule the shagreen was still present. This might strengthen the contention of Butler, that the shagreen is the function of the hyaline capsule itself. In this case any reflection from the epithelium and superficial lens fibers (Gullstrand and Vogt) might only be auxiliary to the formation of the shagreen, in which no epithelium IS present. In Vogtâ€™s cases the anterior capsule in the free part seemed slightly more taut than the posterior. Also both parts became flaccid following the instillation of pilocarpine drops.
Capstdar Folds. The presence of capsular folds is always an indication of shrinking of the lens cortex. Before the days of bio
BIOMICROSCOPY OF THE EYE
microscopy, clinical descriptions of hypermature cataracts included little concerning the presence of capsular folds. Because of the underlying opacification, it is ordinarily impossible to determine
whether the posterior capsule undergoes folding, although anatomically this is quite possible. Folds of the anterior capsule occur not only in hypermature cataract but also in cataracta complicata and in traumatic cataract as well. In complicated cataract it has been noticed that dispersed iris pigment can be deposited on folds in the form of brown stripes. Vogt mentions the presence of capsular folds in cases of so-called "soft juvenile complicated cataractâ€ where they have bluish tints in direct focal light. Ordinary folds, like vacuoles, are best seen as doubly-reflecting lines in retro-illumination or by indirect illumination (Fig. 406). With this form of illumination they remind us of folds of Descemetâ€™s membrane, frequently having an irregular "wormlikeâ€ course and often branched (Fig. 408). Their average width has been estimated as from 0.0 j mm. to 0.5 mm. Flowever, like folds of Descemetâ€™s membrane, their length varies greatly, and it is not unusual to follow a single fold across the
PRESENILE AND SENILE CATARACT IHl
entire pupillary opening. Often, owing to the opaque background of the cortex, these capsular lines cannot be seen distinctly in direct focal illumination.
Fig. 409. Anterior and posterior saucer cataract. Diffuse view.
CupuLiFORM .Cataract (Anterior and Posterior Saucershaped Cataract - Cataracta Scutellaris)
Although the so-called "saucer-shapedâ€ cataract is commonly considered as principally posterior (just in front of the posterior capsule) , a similar type may be found just below the anterior capsule (Fig. 409 ) . Characteristically, these forms of senile opacity are usually restricted to a single layer and are composed of vacuoles and granular material. In most instances they tend to be more densely developed in the axial regions and hence cause visual disturbances at an early stage.
Anterior Saucer Cataract. Anterior saucer cataract is usually associated with posterior saucer cataract or with other cortical and nuclear senile lens opacities. In diffuse illumination it appears as a whitish starlike figure, the branches of which radiate from a central
Fig. I. Anterior cupuliform (saucer type of senile cataract) cataract. Diffuse illumination.
Fig. 2. Same as case in Figure i, as seen by direct focal illumination. Optic section.
Fig. 3. Posterior cupuliform (saucer type). Early. Diffuse illumination.
Fig. 4. Same as case in Figure 3, by direct focal illumination. Optic section.
Fig. 5. Anterior and posterior cupuliform (saucer-like) opacities. Composite view. Direct focal illumination. Optic section.
Fig. 6. More advanced posterior cupuliform (saucer-like) cataract. Diffuse illumination.
Fig. 7. Same case as shown in Figure 6, showing details of vacuolar degeneration. Direct focal illumination. High power.
Fig. 8. Same as case shown In Figure 7, viewed in specular reflection.
PRESENILE AND SENILE CATARACT
axial opacity. (See Fig. 406; Plate LXIX, figs. 1,5.) However, in the early stages it may not show any radiations and resembles the faint subcapsular opacities observed in mature and hypermature cataracts which by retro-illumination are seen to be composed of fine vacuoles. Located subcapsularly, the opacity tends to be thin and lies in one plane. In direct focal light the grayish opacity appears sievelike with dark round holes, reminiscent of the structures seen in band-form keratitis. (See Vol. I, page 345.) These dark holes represent vacuoles the contents of which are less relucent than the surrounding gray area. The lesion starts in the axial region and progresses very slowly in a radiating manner.
Posterior Sancer Cataract. Posterior saucer cataract is one of the common forms of senile cataract. It is characterized by the presence of a single (rarel)'^ double) layer of opacity adjacent to, or just in front of, the posterior capsule (Plate LXIX, figs. 5, 6, 7, 8) . Similar to the anterior variety, it is composed of a thin sievelike vacuolar and granular substance. Before the days of biomicroscopy, its exact location, i.e., in front of the posterior capsule, was not recognized. As seen with the ophthalmoscope (when well developed) it was considered as a posterior lamellar cataract. When combined with nuclear cataract or fairly well-developed cortical changes, the opthalmoscopic diagnosis of posterior saucer cataract may become difiicult. Because of its axial location, visual loss is rapid and extraction may be required in spite of the black appearance of the pupil. In this way it differs from the other types of senile cataract, e.g., incipient cortical and nuclear opacities, which may require years or decades before seriously interfering with central vision. It is rare indeed to find posterior saucer cataract developed to any degree without the concomitant presence of nuclear cataract and at least a few signs of incipient cortical changes (water-slits, spokes, cuneiform opacities, etc. ) . When the opacity is centrally located, it may be seen through an undilated pupil, provided the angle between illumination and observation is very narrow. However, frequently the opacity may be paracentral or peripheral even in its early stages and then dilation of the pupil becomes diagnostically necessary. With the narrow
BIOMICROSCOPY OF THE EYE
beam its exact situation is easily determined as well as its peculiar composition. When employing the prefocal or postfocal part of the beam (diffuse light), its entire saucer-like shape, corresponding to
Fig. 410. Posterior saucer cataract with a few anterior subcapsular opacities arranged in a
the curve of the posterior capsule, and its composition can be seen. It has been pointed out that the appearance of the opacities varies although their different aspects may blend one into the other. First there is the type in which the opacity appears as a thick yellow mat with vacuoles within or superimposed on it. The vacuoles in this form resemble small circles or rings with dark contours and light yellow centers. The second form is thinner (allowing transillumination with the light of the ophthalmoscope) and resembles a sieve. It consists of a thin grayish background punctuated by dark round holes of varying sizes and in general not unlike the appearance of the opacity of band-form keratitis (Fig. 410). (See Vol. I, page 345.) As the substrate of the latter type thickens, it tends to form an intermediary type approaching the thicker and yellower first form. Occasionally a posterior saucer cataract may be composed of a double layer, the ends of the anterior one joining the one behind it peripherally, resulting in a sort of meniscoid structure. The tendency to the formation of a similar meniscus-like double layer opacity has also been reported in irradiation cataract.
PRESENILE AND SENILE CATARACT 1147
It is interesting to speculate why this type of change, which in some ways resembles cataracta complicata so that at times it is difficult to differentiate between them, is so characteristic of the deeper parts of the posterior cortex. Perhaps the absence of epithelium is a factor. Also it may be -that the process of nuclear sclerosis extends backward into the posterior cortex to a greater extent than it ordinarily does anteriorly, leaving vulnerable only a thin subcapsular layer of young fibers. At any rate posterior saucer-shaped cataracts spread out in a flat way in front of the posterior capsule and follow its curvature. Its anterior surface is more or less sharply defined showing little or no tendency to invade the posterior cortex or posterior adult nucleus in an anterior direction. This, together with the more porous consistency and the vivid color display in complicated cataract, helps to differentiate them.
Undoubtedly the biomicroscopic examination of the lens in older persons has demonstrated the high frequency with which the opacification of the nucleus occurs and the important role that it plays in contribution to senile cataract. We are now able not only to discern the earliest manifestation of nuclear change but also to follow its customary slow development over long periods. With the narrow beam, its presence and progress can be determined even when cortical changes are marked. The characteristic change of nuclear cataract, i.e., a uniform cloudiness, does not cause severe visual impairment (as compared to cortical or cupuliform cataract) until discoloration leads to cataracta brunescens or nigra or is complicated by the formation of posterior saucer cataract. In my opinion, it is very rare indeed not to find posterior saucer cataract and anterior cortical changes associated with a well-developed nuclear cataract. This might indicate that nuclear cataract may play a role in the formation of cortical changes. On the other hand, the nucleus often may remain relatively clear for a long time in the presence of an advancing cortical cataract, but in the end it always participates in the process of opacification. It should be pointed out that nuclear opaci
BIOMICROSCOPy OF THE EYE
fication is not only a symptom of senile cataract but may also accompany rapidly developing cataracta complicata, especially those secondary to severe intra-ocular disease, e.g., glaucoma, retinal separation, and infections.
As was mentioned in the chapter discussing the physiologic aging processes of the lens (page ioi8) the nucleus gradually undergoes a process of hardening or sclerosis. As part of these changes the relief of the adult nucleus becomes increasingly reflective and prominent. This serves further to help biomicroscopic distinction between the nucleus and the cortex. It should be remembered, however, that the zone or band forming the so-called "surfaceâ€ of the adult nucleus is not a sharp one but in adults and older persons is rather an area of definite sagittal thickness, as evidenced by its rather cloudy and ill-defined demarcation when viewed in optic section. Evidentally physiologic sclerosis is not strictly limited to the central parts of the lens but may also involve the deeper parts of the cortex. Except for the above mentioned phenomena, physiologic sclerosis per se does not result in opacification, at least of sufficient density to be recognizable biomicroscopically as a relucent haze. When a definite milkiness is found within the nucleus, we are already dealing with cataractous development.
Observation with the narrow beam shows that opacification of the nucleus occurs in a definite pattern and starts in a well-defined zone. The first indications of increase in relucency are seen within the two biscuit-shaped inner embryonal nuclei (Fig. 41 1 A, B). According to Koby, the anterior inner embryonal nucleus tends to become involved a little in advance of the posterior one, but Vogt states that he has never seen the anterior inner embryonal fetal nucleus opaque and the posterior one clear or vice versa. The dark central interval may remain recognizable for a long time (Fig. 41 1 B) but in the latter stages it may no longer be identified as such. An interesting and characteristic finding is that the anterior and poste
Vogt states that the widely held opinion that the as yet clear sclerosed nucleus lacks vital qualities and hence is to be considered as a kind of dead foreign body within the living lens is false. Nuclear sclerosis should be considered as a conserving process, which inhibits degeneration and in this sense tends to preserve vision for a longer time.
PRESENILE AND SENILE CATARACT
rior embryonal fetal sutures tend to become opaque, standing out as distinct, sharp, white figures, against the grayish-white (opaque) background of the affected inner embryonal fetal nuclei. The central
Fig, 41 1. Early nuclear cataract, a. The beam (optic section) passing through the lens is observed with the unaided eye. Note smaller posterior capsular opacity and faint cortical changes. B. Same as A, 15 X magnification.
clouding progresses outwardly in both directions gradually involving both outer embryonal fetal nuclei. A characteristic finding at this stage, which was brought to our attention by Vogt, is the fact that the central opacity is always separated from the adult nuclear stripe by a dark (lucid) interval in all directions (Fig. 41 1 B). However, although this â€œlucidâ€ interval may remain present for months or years, eventually as the reflection of the adult nucleus stripe increases, it becomes opaque so that in the end the central opacity merges with the highly reflecting adult nucleus stripe. As a result the nuclear cataract extends continuously from the anterior nuclear stripe to the posterior one. The opaque nucleus is then separated from the stripe of discontinuity by a more or less dark cortical band, depending of course on the relucency of the cortex which in turn is governed by cataractous changes within it.
In all cases, even with higher powers of magnification, the uniform opacification, causing the nuclear haze, cannot be resolved into any definite morphologic elements. Many writers, however,
BIOMICROSCOPY OF THE EYE
have described a dustlike composition. This difference in behavior between the cortex and nucleus in this regard is striking. In the former gradual coagulation and liquefaction results in the formation
Fig. 412. Nuclear cataract further advanced; cortical changes are well developed.
of droplike elements with more intense opacification. As previously suggested this variation in the response between the cortex and the nucleus is probably due to differences in consistency (sclerosis of the nuclear fibers) rather than to any specific chemical change peculiar to either part. Because of the diffuse type of opacification common to nuclear cataract, it is possible with the narrow beam and sharp focusing to penetrate through the most opaque nucleus, provided the anterior cortex is not entirely opaque. It is now well known that nuclear cataract is closely associated with "lens of double focusâ€ and is a forerunner of cataracta brunescens and nigra.
Nuclear Cataract with DoiMe Foc7ts. This is not so rare a phennomenon in senile cataract as thought; and has frequently been over
PRESENILE AND SENILE CATARACT
looked. It now seems that, owing to a moderate opacification of the fetal nuclei (nuclear cataract) with retention of a dark surrounding interval, a difference in refractive index between the cortex and the nucleus results in a central myopia. There is a coexistent peripheral emmetropia, hypermetropia, or a smaller degree of myopia than that which occurs axially.
According to the records, this condition was first hinted at by L. Muller (1894) who published an observation of Salzmann concerning a lens with double focus. One year later, Demicheri described the condition in three patients and, because of its resemblance skiascopically to lenticonus, called it "false lenticonus.â€ Following this report, several other authors made similar observations (Guttman,"*Â®*^ v. Szily, Halben, v. Hess^â€˜â€˜). Demicheri found that a severe disturbance of vision resulted from the fact that the axial parts of the lens showed a higher refraction (myopia) than did the periphery, the two being separated by an intermediary zone concentric to the lens surface. He concluded that the trouble lay in the difference between the indices of refraction of the cortex and the nucleus, as if a stronger refracting nucleus were located within a weaker refracting cortex. The fact that the inner nuclei were highly reflective (opaque) was not stressed by the earlier writers, perhaps because in many instances, the opacity was not visible ophthalmoscopically or only insignificantly so. But in 1903 von Szily with the method of oblique illumination at his command already spoke of the increase in inner reflection and suspected the presence of a cataract.
However, Vogt in 1923 stressed the fact that biomicroscopically the lens with double focus was dependent on nuclear cataract. It is found that the contours of the opaque part of the nucleus were more curved than those of the surface of the adult nucleus or capsule. In other words the great difference in index of refraction in the axial part is brought about by a pathologic cataractous process. It should be emphasized that the nuclear opacity is not total but only involves the fetal nucleus. The opaque fetal nuclei are separated
BIOMICROSCOPY OF THE EYE
from the surfaces of the adult nucleus by a "lucidâ€ interval. It will be seen that the condition of double focus can occur only with the average pupillary width provided the central axial opacity is sufficiently small (not over 4.5 mm.) to permit vision through it and at the same time through the unaffected peripheral parts around it. A form of double focus can also be demonstrated when the nuclear opacity is larger provided the pupil is dilated and a steneopaeic slit is employed. Occluding the central part of the slit it will be found that the distant vision is better (less myopic) than when direct central vision through the unoccluded slit is permitted. The fact that only in isolated cases does a lens with double focus occur, considering the great frequency of nuclear cataract, is substantiated clinically in that in most cases the nuclear opacification occupies a greater area. The further outward the opacification extends (i.e., toward the surface of the adult nucleus) the less curved will its surface be. Most cases of lenses with double foci occurred in older persons who were myopic. In these cases "progressiveâ€ myopia may occur within a few months.*â€™â€™ These patients when looking in the distance seem to see better than their degree of myopia warrants owing to the fact that they employ peripheral vision. Among the other distressing symptoms are diplopia and polyopia. In lenses with double foci the nuclear opacification not only progresses with time, in which case the troublesome symptoms decrease, but also there is a strong tendency for them to develop color changes leading to cataracta brunescens and nigra. As the opacification develops the "lucidâ€ area between it and the surface of the adult nucleus finally becomes relucent (Plate LXX, fig. 5 ) . From the very onset the reflection from the surface of the adult nucleus is increasingly marked. Another feature, common to nuclear cataracts, is the appearance of the embryonal sutures, which stand out as white lines; also the fact that the dark interval, located between the inner fetal nuclei, may be identified as such in the early stages only. Later on it also becomes
Vogt pointed out that eyes with axial myopia are predisposed to this condition. Likewise cataracta brunescens and nigra is relatively frequent in axial myopia as well as cataracta complicata secondary to intra-ocular disease. Lenses with double focus are rare in persons under 35 years of age. although he found one in a lo-year-old boy.
PRESENILE AND SENILE CATARACT
cloudy. Diabetes is another condition in which a rapid progressive myopia may suddenly develop. However, as Vogt has pointed out, diabetic myopia can occur without showing any definite or typical lens changes biomicroscopically. Also sudden myopia may occur during the course of sulfonamide chemotherapy.
CATARACTA BRUNESCENS AND NIGRA
One of the features characteristic of nuclear cataract is the frequently found color change in its deeper parts. As discussed on page 1012 under "physiologicâ€ senile alterations, it is rare indeed not to find some yellow or yellowish brown coloration in the posterior subcapsular regions of the lens in persons over 6o years of age who still have normal vision. In studying such cases, I have found that frequently the yellow coloration begins at the posterior capsule and advances forward in the posterior cortex up to the surface of the posterior adult nucleus. Undoubtedly the "warmâ€ coloration of the deeper parts of the lens acts as a filter and as such would affect vision in a way similar to tinted spectacles. Any greater reduction (in the absence of other changes) would have to be attributed to the associated nuclear opacity. At any rate, in many cases of nuclear cataract, further extension of this change results in the appearance of a tan, orange, or red to brownish-red color (Plate LXX, figs, i, 2, 3, 4). The terms "cataracta brunescens,â€ "rubra,â€ and "nigraâ€ are employed to express the varying degrees of color intensity seen. In the extreme state, ophthalmoscopically, we find a black, nontransilluminable pupil (the so-called "cataracta nigraâ€)."* It should be pointed out that this intense coloration, although associated with it, is probably not entirely dependent on nuclear sclerosis and cataract alone. Even in the presence of complete nuclear opacification, the reflex from the deeper parts may only show a weak yellow color, not unlike that seen physiologically in age. The color change which is most marked in the posterior cortex gradually extends forward until
With the moderately narrow beam, however, in this instance it will be seen that the color is an intense dark red, increasingly so as one approaches the deeper parts. With diffuse illumination it is evident to a lesser degree and consequently the posterior half of the nucleus will appear darker or blackish. Red-free light does not penetrate at all and the posterior parts will be jet black.
Fig. I. Nuclear cataract (brunescence) . Direct focal illumination. Low power. (After Messmann.)
Fig. 2. Nuclear cataract. Direct focal illumination. Optic section.
Fig. 3. Nuclear cataract (Rubra). Direct focal illumination.
Fig. 4. Nuclear cataract. Direct focal illumination.
Fig. 5. Nuclear cataract. Optic section. Direct focal illumination.
Fig. 6. Nuclear cataract with central area of unusual vacuolar degeneration. (Courtesy of Dr. D. Gordon.)
PRESENILE AND SENILE CATARACT 1157
it fades within the nucleus. The most anterior parts of the adult nucleus and the deeper and middle anterior cortex frequently have a decided greenish-gray tinge, in contrast to the bluish-gray one seen normally. Thus, within a single lens, we may find a gradual "dilution of color,â€ varying posteriorly from a dark red or brown to a light yellow and greenish tinge. As the process develops into a definite cataracta brunescens, rubra, or nigra, the brownish or deep red color extends itself almost to the anterior adult nuclear surface where it changes into orange and then to greenish-gray. Only the anterior subcapsular region (in the absence of cortical changes) may still retain the original bluish-gray opalescence characteristic of the normal lens, Vogt postulates that color variations are simply an expression of dilution of one type of dye stuff. He compares it to the color changes seen with gradual dilution of certain colored chemical substances, e.g,, lysol. In concentrated form a thin layer of lysol solution appears red to red-brown while a thicker layer of the same concentration is black. Highly diluted, it is pale yellow. However, Bellows refers to the work of Walls and Judd ( 1933) and Walls (1931, 1940)Â°Â®^â€™Â®Â®Â® on the coloration of lenses in lower animals. They found that in certain animals whose lenses were yellow the intensity of this color was related to the degree of exposure of these animals to bright light. They were able to extract a yellow pigment which they called "lentiflavinâ€ and which apparently differs from the pigment in cataracta brunescens and nigra.
Although the fainter yellow coloration occurs in practically all persons of great age especially those with senile myopia, welldeveloped cataracta brunescens and nigra, according to all available statistics, is rare. Rollet and Bussy,â€™â€™Â®^ gathering data from several authors, found it 48 times in 15,763 cases of cataract extractions. Also coloration of both lenses in the same individual can differ markedly normally or in cases where severe disease of the inner eye exists (cataracta complicata).
For a long time there has been considerable dispute concerning the mechanism producing these color changes, especially whether it is derived from extra- or intralenticular sources and whether it is caused by purely physico-optical phenomena or by the actual production of pigment."' Suffice to say here that modern opinion holds that the coloring represents pigment formed endogenously and that it probably has a â€œmelanin-like structureâ€ (Bellows). It is interesting to note that in one place in his atlas, Vogt follows other writers (Hess, Busacca and others) in favoring the physical theory for the explanation of the color and in another he speaks of the presence of a dyestuff (i.e., the color pigment may be formed by a transformation of the lens proteins). The current theory is that melanin or â€œmelanoid-like substancesâ€ are derived from a precursor, tyrosine. Since free tyrosine is only found in cataractous lenses, it follows that decomposition of lens protein is a prerequisite. In a similar way conjunctival and corneal pigmentation (Stahliâ€™s line) may be a result of the liberation of premelanotic substances in the pathologically changed protein content of these tissues (see Vol. I) .
For a more complete discussion of this problem the reader is referred to other sources, e.g., Hess, 1911;^"â€œ Rollet and Bussy, 1921;Â®Â®^ Vogt, 1931;Â®Â®Â® Gilford and Puntenney, i933;4'*s and Bellows, 1944.Â®Â®*
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