Disorder - Coloboma

Organ Systems Involved
Nervous/sensory

Alternative disorders described within LIDA

Choroidal coloboma; Dermoids; Microphthalmia; Optic nerve coloboma; Persistent pupillary membrane; Retinal dysplasia

Alternative Names
Eyelid agenesis

Presenting Signs

A coloboma is when one of the structures in the eye is absent or defective. It may involve the lens, eyelid, iris, retina, choroid or optic disc. Eyelid coloboma is the most common congenital eyelid abnormality found in cats. It is a defect in the development of the upper eyelid and ranges in its severity: it may be present as a small ‘notch’ in the margin of the eyelid, or as much as two-thirds or more of the upper eyelid and its tissue lining (conjunctiva) may be missing. This problem usually occurs in both eyes. Small abnormalities in the eyelid may cause no problem, but more severe defects can cause disease of the cornea. The eyelids may be unable to close properly and cannot protect the eye from physical trauma, and adjacent facial hair rubbing against the cornea may cause ulceration of the cornea. If other eye structures are absent the vision will be affected.

Breeds Affected
Burmese
Persian
Siamese


Treatment

Surgical: the defect is closed using surrounding skin, or a new eyelid is created from adjacent skin and conjunctiva.

PubMed References
Coloboma

Contributor
Alison Wardman