Sensory - Vision Abnormalities

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Introduction

These notes introduce the abnormal development of the eye and vision associated structures.

Anophthalmia (absence of an eye) and microphthalmia (small eye within the orbit) have a combined birth prevalence of approximately 30 per 100,000 population.

Genetic factors include developmental transcription factors required for inductive/developmental events in the structure of the eye and retina development.

Environmental factors include gestational-acquired infections, maternal vitamin A deficiency, smoking, X-ray exposure, solvent misuse and thalidomide exposure.

Some Recent Findings

Targeted 'next-generation' sequencing in anophthalmia and microphthalmia patients confirms SOX2, OTX2 and FOXE3 mutations"Anophthalmia/microphthalmia (A/M) is caused by mutations in several different transcription factors, but mutations in each causative gene are relatively rare, emphasizing the need for a testing approach that screens multiple genes simultaneously. We used next-generation sequencing to screen 15 A/M patients for mutations in 9 pathogenic genes to evaluate this technology for screening in A/M."

Neonatal Vision

Vision in the developing infant can be assessed by a number of tests for: central vision, stereoscopic (binocular) vision, refraction, color vision, contrast vision, scotopic/photopic (dark/light) vision (retina/rods), and tracking (following and saccades), (retina, oculomotor muscles).

Preterm infants have been shown to develop a number of vision related abnormalities including: visual impairment, oculomotor abnormalities, and refractive error.

normal behaviour	cranial nerves

Links: Movie - Newborn normal behaviour

Anophthalmia

Anophthalmia and microphthalmia

Anophthalmia is clinical description for the absence of an eye. Gene mutation of SOX2, a developmental transcription factor, has been associated with this condition.

Microphthalmia

Microphthalmia is clinical description for the presence of a small eye within the orbit and occurs in up to 11% of blind children.

Ferda Percin E, Ploder LA, Yu JJ, Arici K, Horsford DJ, Rutherford A, Bapat B, Cox DW, Duncan AM, Kalnins VI, Kocak-Altintas A, Sowden JC, Traboulsi E, Sarfarazi M, McInnes RR. Human microphthalmia associated with mutations in the retinal homeobox gene CHX10. Nat Genet. 2000 Aug;25(4):397-401.

Syndromic microphthalmia-9 can be caused by mutations in the Stimulated by Retinoic Acid 6 (STRA6) gene. OMIM - MCOPS9

Bardet-Biedl Syndrome

(BBS) is an abnormality with triallelic inheritance and is characterized by a range of multisystem abnormalities incliuding postnatal developmental blindness.

cone-rod dystrophy truncal obesity postaxial polydactyly cognitive impairment neural development male hypogonadotrophic hypogonadism female genitourinary malformations renal dysfunction (More? OMIM - Bardet-Biedl syndrome | GeneReviews - Bardet-Biedl syndrome)

Pax6 Mutation

Phenotypes of wild-type (top) and PAX6 ortholog mutations (bottom) in human, mouse, zebrafish, and fly.

Human mutations may result in aniridia (absence of iris), corneal opacity (aniridia-related keratopathy), cataract (lens clouding), glaucoma, and long-term retinal degeneration.

Congenital Rubella Syndrome

Links: Abnormal Development - Rubella Virus

World Statistics

Sweden

Rate of anophthalmia decreased from the early 1970s from 0.4 to 0.2 per 10,000 births. Non-eye malformations were more common at anophthalmia (63%) than at microphthalmia (30%) Maternal smoking in early pregnancy seemed to increase the risk for anophthalmia or microphthalmia in the absence of a coloboma.

United Kingdom

1988-94 prevalence of anophthalmia and microphthalmia was 1.0 per 10,000 births.

USA California

1989-1997 prevalence per 10,000 livebirths and stillbirths for anophthalmia was 0.18 and for bilateral microphthalmia was 0.22. Risk of anophthalmia was approximately twofold among multiple births compared to singletons. (More? Shaw GM, etal., 2005)

References

Online Textbooks

• Developmental Biology (6th ed.) Gilbert, Scott F. Sunderland (MA): Sinauer Associates, Inc.; c2000. | Chick embryo rhombomere neural crest cells | Some derivatives of the pharyngeal arches | Formation of the Neural Tube | Differentiation of the Neural Tube | Tissue Architecture of the Central Nervous System | Neuronal Types | Snapshot Summary: Central Nervous System and Epidermis

• Neuroscience Purves, Dale; Augustine, George J.; Fitzpatrick, David; Katz, Lawrence C.; LaMantia, Anthony-Samuel; McNamara, James O.; Williams, S. Mark. Sunderland (MA): Sinauer Associates, Inc. ; c2001 Early Brain Development | Construction of Neural Circuits | Modification of Brain Circuits as a Result of Experience

• Molecular Biology of the Cell (4th Edn) Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter. New York: Garland Publishing; 2002. Neural Development | The three phases of neural development

• Clinical Methods 63. Cranial Nerves IX and X: The Glossopharyngeal and Vagus Nerves | The Tongue | 126. The Ear and Auditory System | An Overview of the Head and Neck - Ears and Hearing | Audiometry

• Health Services/Technology Assessment Text (HSTAT) Bethesda (MD): National Library of Medicine (US), 2003 Oct. Developmental Disorders Associated with Failure to Thrive

• Eurekah Bioscience CollectionCranial Neural Crest and Development of the Head Skeleton

Reviews

Bookshelf vision development

Search Pubmed

• Pubmed vision developmental abnormalities | [Congenital Rubella Blindness

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Cite this page: Hill, M.A. (2024, April 16) Embryology Sensory - Vision Abnormalities. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Sensory_-_Vision_Abnormalities

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G