-Coloboma can be unilateral or bilateral
-Bilateral colobomas are usually inherited in an autosomal dominant fashion
-If fetal fissure fails to close posteriorly, then a coloboma affecting the retinal pigment epithelium, neurosensory retina or choroid may occur
-Can be associated with lens coloboma due to persistence of mesodermal vascular remnants that prevent development of zonules in that area leading to flattening of the lens edge
-Mutation in PAX6 gene has been reported in association with syndromic forms of colobomata.
FEATURES:
-White background of the sclera usually showing a glistening white sheen replaces normal color of the fundus
-Typically, coloboma is oval.
-Usual location is downwards and inwards.
-Posterior end frequently stops short of the disc
-Anterior end sometimes reaches forwards beyond the limits of ophthalmic examination, due to involvement of the ciliary body region as well
-Edges are pigmented
INVESTIGATIONS:
-Systemic investigations or genetic tests for syndromes
-USG - in hazy media
-OCT - helps in identifying retinal breaks
MANAGEMENT:
Amblyopia:
-Unioculat coloboma not involving the macula can be associated with refractive errors that need prompt correction to avoid development of amblyopia
-In cases with bilateral coloboma, severe refractive errors may lead to ametropic amblyopia
-RD is a frequent complication of choroidal colobomas
-Prophylactic laser photocoagulation at the edge of coloboma
-Surgery for RD usually involves pars plana vitrectomy, endolaser photocoagulation
Image from Rajan Eye Care Hospital
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