Week 2- Conditions of the Uvea

Question 1

What is subalbinism?

Answer 1

Melanin absent from anterior stroma but posterior iridal epithelium is pigmented > Blue iris
Can be associated with colobomata, hypoplasia or absence of tapetum, iris hypoplasia, corectopia,
choroideal hypoplasia.

Question 2

What is Merle ocular dysgenesis?

Answer 2

Gene carried by various breeds including Sheltie, Great Dane, OES, rough and smooth collies and
Australian shepherd.
Can be associated with multiple ocular abnormalities, including microphthalmos, cataract, retinal
dysplasia and retinal detachment.

Question 3

What is iris hypoplasia?

Answer 3

*More common in heterochromic eyes
*Failure in closure of optic fissure
*Bulge forward
*Dark area within dorsal iris

Question 4

What is subalbinism?

Answer 4

*Heterochromic iris
* Partial thickness coloboma (absent/thin overlying iris
stroma; dark pigmented iridal epithelium thus visible)
* Red fundus reflex- may indicate lack of tapetal
development and/ or fundus pigmentation