This is an excellent example – I would say an extreme example – of iris melanosis in the eyes of an elderly cat. The picture caught my eye (excuse the pun). It comes from the Reddit.com website on which a member of that site (u/lilbeewin) posted a picture of her cat with the title: “Lost my best friend today. August 1999-July 28, 2021“. It must have been emotionally painful. The cat was a brown tabby and the eyes are extraordinary because the brown spots are all over the iris of the eye except for the centre, the location of the pupil which in this cat is a slit because the light is reasonably bright.
This discolouration of the rim of the iris look like freckles and usually occurs in middle-aged to older cats. The condition typically does not cause any problems but in severe cases my research tells me that it may result in dysfunction of the iris and sometimes increased eye pressure which is called glaucoma. I sincerely hope that the best friend referred to above did not suffer from these conditions because the photo does show, it seems to me, an extreme version of freckles of the iris.
Iris melanosis can be confused with iris melanoma, a potentially serious type of cancer. You might want to see your veterinarian just in case. Iris melanosis is benign but apparently it can sometimes progress into iris melanoma. Melanomas can metastasise to other parts of the body. Often the freckles are quite slight and not as shown in the photograph on this page. The spots might start small and gradually increase in dimension. Multiple spots can grow in size and then merge. One difference between iris melanomas and iris melanosis is that the former is lumpy causing the surface to be raised whereas the latter is flat and does not protrude from the iris.
The cat in the picture lived to a very good age, almost 22 years.
MORE ON CAT EYES: