Why is there a dark, spreading spot on my aging cat's iris?

The type of lesion on Bisou's iris (the pigmented part of the eye) looks most like a cyst (iridal or iridociliary cyst), which is a fluid-filled structure that can change in size. That said, it's important to have this area evaluated to differentiate between a cyst and a mass, as they can appear pretty similar. Diagnostic testing, such as transillumination and ultrasound are often used to differentiate between these two issues. Since this has been changing so slowly, it certainly isn't an emergency, but it's best to have this issue evaluated in the coming weeks. I hope that everything goes well!

It looks like Memo could have changes to the iris due to anterior uveitis or inflammation in the eye. This can cause the pupil to become smaller and the iris to change colors. It’s also possible that Memo has a growth on this eye. I would recommend seeing your veterinarian so they can examine Memo’s eye in person. They may want to check his eye pressure.

It is not uncommon for cats to develop brown or black spots on the iris. A pigmented area on the iris can be benign or malignant, and differentiating them is sometimes difficult. My guess is that these spots are what we call iris nevus. These are benign (like freckles). Since she has so many, this would be called iris melanosis. Iris melanosis is classified as benign, but in time, it may progress to a malignant melanoma. Although melanomas are rare in cats, the eye is the most common site for it to show up. The first hint that this could be melanoma is rapid growth. If you know the spot(s) is getting larger quickly, that is a warning sign. If the shape of the pupil has become deformed as it dilates and constricts, that is another potential red flag. I suggest you have Dixie examined by your vet to get a diagnosis. She needs a thorough exam with a ophthalmoscope. Hope this helps. Best wishes.

I see what you are seeing from the pictures. The pupil is just an opening in the iris (colored part) and what sits inside the eye (behind the pupil, what you see though the pupil) are the lens and the contents of the back of the eye (fundus including retina, etc.). A cloudiness to the eye can occur due to inflammation (uveitis), lens related changes (nuclear sclerosis or cataracts), or sometimes due to cellular infiltrate in the eye. It is good that there are no vision changes and that the eye is comfortable. A cause for this haze should be able to be readily identified by an eye exam by your vet. Dependent on the cause monitoring may all that is required. I hope this helps and thank you for using Petco Pet Education Center, formerly Petcoach!

Brittany is beautiful! It is common that cats will have color changes in the iris (the colored part of the eye) that will appear darker or almost like a freckle. If your vet has examined Brittany and told you that it is nothing to worry about, then I would just monitor it. It should not change appearance over time or appear to be getting thicker. If that happens, then I would have your veterinarian examine it again. Good luck! I hope that was helpful and answered your question. Thanks for using Petco Pet Education Center, formerly Petcoach.

This looks like a condition called iris atrophy. Iris atrophy is typically a benign condition that does not cause any major concern, but I would recommend having Andromeda examined by your vet for a brief eye exam up close with special instrumentation to verify this suspicion. Other possible causes would be an eye freckle or eye mass. Best wishes with your pet Andromeda and I hope that things work out well for her eye moving forward. Take care : )

That new pigment around Butter’s pupil is concerning for inflammation of the iris or melanoma. Cats can get uveitis (which is basically inflammation of the internal eye structures) for many different reasons. Hyperthyroidism can also sometimes change the pigment. Melanoma is a cancer that can affect the eye of a cat at any age. I recommend to make an appointment with your veterinarian. That will at least get you started on the right path. Fingers crossed it’s nothing serious! Please post again with any further questions.