Vision - Lens Development

Embryology - 5 Dec 2023 Expand to Translate
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Introduction

Human lens development (Carnegie stage 22, Week 8)

The lens or crystalline lens or aquula (Latin, aquula = a little stream) has a key role in focussing light (with the cornea) upon the neural retina. The lens embryonic origin is from surface ectoderm of the sensory placodes that form in the head region (More? Placodes).

The lens focusses by refracting light as it passes through the biconvex lens, which can be altered in shape (accommodation) by surrounding ciliary muscles. These ciliary muscles are activated (contracted) by parasympathetic innervation from the ciliary ganglion itself innervated by the oculomotor nerve (Cranial Nerve CN III).

The lens has recently been shown in the chicken model to not be required for specification of the iris and ciliary body.^[1]

Historic Embryology - Vision
Historic Embryology: 1906 Eye Embryology \| 1907 Development Atlas \| 1912 Eye Development \| 1912 Nasolacrimal Duct \| 1917 Extraocular Muscle \| 1918 Grays Anatomy \| 1921 Eye Development \| 1922 Optic Primordia \| 1925 Eyeball and optic nerve \| 1925 Iris \| 1927 Oculomotor \| 1928 Human Retina \| 1928 Retina \| 1928 Hyaloid Canal \| Historic Disclaimer

Some Recent Findings

Review - The cellular and molecular mechanisms of vertebrate lens development^[2] "The ocular lens is a model system for understanding important aspects of embryonic development, such as cell specification and the spatiotemporally controlled formation of a three-dimensional structure. The lens, which is characterized by transparency, refraction and elasticity, is composed of a bulk mass of fiber cells attached to a sheet of lens epithelium. Although lens induction has been studied for over 100 years, recent findings have revealed a myriad of extracellular signaling pathways and gene regulatory networks, integrated and executed by the transcription factor Pax6, that are required for lens formation in vertebrates."

Pax6-dependent, but β-catenin-independent, function of Bcl9 proteins in mouse lens development^[3] "While lens development is critically dependent on the presence of the HD1 domain, it is not affected by the lack of the HD2 domain, indicating that Bcl9/9l act in this context in a β-catenin-independent manner. Furthermore, we uncover a new regulatory circuit in which Pax6, the master regulator of eye development, directly activates Bcl9/9l transcription."

On the growth and internal structure of the human lens^[4] "Growth of the human lens and the development of its internal features are examined using in vivo and in vitro observations on dimensions, weights, cell sizes, protein gradients and other properties. In vitro studies have shown that human lens growth is biphasic, asymptotic until just after birth and linear for most of postnatal life."

Activated Ras alters lens and corneal development^[5] "The murine lens and cornea have a common embryonic origin and arise from adjacent regions of the surface ectoderm. ...Collectively, these results suggest that Ras activation a) induces distinct sets of downstream targets in the lens and cornea resulting in distinct cellular responses and b) is sufficient for initiation but not completion of lens fiber differentiation."

More recent papers
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Development Overview

surface ectoderm -> lens placode -> lens pit -> lens vesicle -> lens fibres -> lens capsule and embryonic/fetal nucleus.

Week 4

Human Embryo Carnegie stage 11

Human Embryo Carnegie stage 12

Human Embryo Carnegie stage 11 optic pit

Week 5

Human Embryo Carnegie stage 13

Week 8

Human Embryo Lens (week 7-8)
Stage 19-23
Carnegie stage 19 (Embryo 409)
Carnegie stage 20 (Embryo 462)
Carnegie stage 21 (Embryo 1358F)
Carnegie stage 22 (Embryo 4339)
Carnegie stage 23 (Embryo 4570)

Reference^[6]

The images below link to virtual slides of the human developing eye at Carnegie stage 22. Click on the image to open or select specific regions from the regions of interest links.

Stage 22 - Eye and Nose

‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides

Stage 22 - Eye

‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides

Virtual Slide - Regions of Interest

Links: Carnegie stage 22 | Embryo Virtual Slides

Molecular Signaling

Wnt mediates lens repression by neural crest cells and Transforming growth factor-β^[7] (open image for full description)

References

↑ Dias da Silva MR, Tiffin N, Mima T, Mikawa T & Hyer J. (2007). FGF-mediated induction of ciliary body tissue in the chick eye. Dev. Biol. , 304, 272-85. PMID: 17275804 DOI.
↑ Cvekl A & Ashery-Padan R. (2014). The cellular and molecular mechanisms of vertebrate lens development. Development , 141, 4432-47. PMID: 25406393 DOI.
↑ Cantù C, Zimmerli D, Hausmann G, Valenta T, Moor A, Aguet M & Basler K. (2014). Pax6-dependent, but β-catenin-independent, function of Bcl9 proteins in mouse lens development. Genes Dev. , 28, 1879-84. PMID: 25184676 DOI.
↑ Augusteyn RC. (2010). On the growth and internal structure of the human lens. Exp. Eye Res. , 90, 643-54. PMID: 20171212 DOI.
↑ Burgess D, Zhang Y, Siefker E, Vaca R, Kuracha MR, Reneker L, Overbeek PA & Govindarajan V. (2010). Activated Ras alters lens and corneal development through induction of distinct downstream targets. BMC Dev. Biol. , 10, 13. PMID: 20105280 DOI.
↑ Streeter GL. Developmental Horizons In Human Embryos Description Or Age Groups XIX, XX, XXI, XXII, And XXIII, Being The Fifth Issue Of A Survey Of The Carnegie Collection. (1957) Carnegie Instn. Wash. Publ. 611, Contrib. Embryol., 36: 167-196.
↑ Grocott T, Johnson S, Bailey AP, Streit A. Neural crest cells organize the eye via TGF-β and canonical Wnt signalling. Nat Commun. 2011 Apr;2:265. PMID21468017 | Nat Commun.

Reviews

Articles

Additional Images

Historic Images

Historic Disclaimer - information about historic embryology pages
Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding. (More? Embryology History \| Historic Embryology Papers)

Human Embryo Lens (week 7-8)
Stage 19-23
Carnegie stage 19 (Embryo 409)
Carnegie stage 20 (Embryo 462)
Carnegie stage 21 (Embryo 1358F)
Carnegie stage 22 (Embryo 4339)
Carnegie stage 23 (Embryo 4570)

Reference^[1]

Glossary Links

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Cite this page: Hill, M.A. (2023, December 5) Embryology Vision - Lens Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Vision_-_Lens_Development

What Links Here?

↑ Streeter GL. Developmental Horizons In Human Embryos Description Or Age Groups XIX, XX, XXI, XXII, And XXIII, Being The Fifth Issue Of A Survey Of The Carnegie Collection. (1957) Carnegie Instn. Wash. Publ. 611, Contrib. Embryol., 36: 167-196.

[PMID17275804-1] Dias da Silva MR, Tiffin N, Mima T, Mikawa T & Hyer J. (2007). FGF-mediated induction of ciliary body tissue in the chick eye. Dev. Biol. , 304, 272-85. PMID: 17275804 DOI.

[PMID25406393-2] Cvekl A & Ashery-Padan R. (2014). The cellular and molecular mechanisms of vertebrate lens development. Development , 141, 4432-47. PMID: 25406393 DOI.

[PMID25184676-3] Cantù C, Zimmerli D, Hausmann G, Valenta T, Moor A, Aguet M & Basler K. (2014). Pax6-dependent, but β-catenin-independent, function of Bcl9 proteins in mouse lens development. Genes Dev. , 28, 1879-84. PMID: 25184676 DOI.

[PMID20171212-4] Augusteyn RC. (2010). On the growth and internal structure of the human lens. Exp. Eye Res. , 90, 643-54. PMID: 20171212 DOI.

[PMID20105280-5] Burgess D, Zhang Y, Siefker E, Vaca R, Kuracha MR, Reneker L, Overbeek PA & Govindarajan V. (2010). Activated Ras alters lens and corneal development through induction of distinct downstream targets. BMC Dev. Biol. , 10, 13. PMID: 20105280 DOI.

[Streeter1957-6] Streeter GL. Developmental Horizons In Human Embryos Description Or Age Groups XIX, XX, XXI, XXII, And XXIII, Being The Fifth Issue Of A Survey Of The Carnegie Collection. (1957) Carnegie Instn. Wash. Publ. 611, Contrib. Embryol., 36: 167-196.

[7] Grocott T, Johnson S, Bailey AP, Streit A. Neural crest cells organize the eye via TGF-β and canonical Wnt signalling. Nat Commun. 2011 Apr;2:265. PMID21468017 | Nat Commun.

[Streeter1957-8] Streeter GL. Developmental Horizons In Human Embryos Description Or Age Groups XIX, XX, XXI, XXII, And XXIII, Being The Fifth Issue Of A Survey Of The Carnegie Collection. (1957) Carnegie Instn. Wash. Publ. 611, Contrib. Embryol., 36: 167-196.

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