Q: Recently, I noticed that the iris of one of my 16-year-old cat’s eyes has gotten darker. It started in the corner and spread throughout the entire eye. It does not appear that the pupil has been affected. Do you think it is cause for concern?
A: Pigmentation of the iris often develops in cats as they get older. In most cases, only one eye is affected. It can affect a small part of the iris, or in some cases, it can involve the entire iris. In the majority of these cases, the pigmentation is benign. However, melanomas of the iris, although uncommon, have been described in cats. To be on the safe side, I’d have your veterinarian check it out. Your best bet would be to have the eye evaluated by a board-certified veterinary ophthalmologist.