Coloboma Figure 1

Figure 1: Coloboma of the right iris (unilateral) in female rat (Maya).
Case history and photos


An obese 18-month-old , black blazed banded dumbo, intact female rat, adopted at 5 weeks old.

History included intermittent urine staining of the fur surrounding the genital area occurring throughout life, and which was briefly treated unsuccessfully with oral antibiotics.

Left eye showed deterioration unrelated to the right eye.

Clinical Signs

The first clear photographs noted a change in Maya’s eyes when she was 5 months old. In these photos a notch can be seen in the right iris. The pupil appeared to point upwards. Pupil reflex (to light) was present.

Her reaction to the environment was similar to some PEWs (pink-eyed white rats), suggesting that she couldn’t see as well as her dark-eyed cage mates.


At 12 months of age she was taken to the vet for a regular check-up. Abnormalities were noticed in both right and left eyes. The vet diagnosed coloboma of the iris of the right eye, and what appeared to be gradual deterioration of the iris of the left eye unrelated to the coloboma.


There is no specific treatment for coloboma.


Maya managed very well despite her eye issues. She and her cage mates lived in a multi-level cage, the interior of which was changed about quite frequently and she was easily able to adapt to changes.


Maya passed away suddenly at 25 months of age. No postmortem histopathology was performed.


Coloboma right eye

Coloboma of the iris-right eye can be noted by the small notched area.

Case history and photos courtesy of Cyzahhe


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