Spontaneous Iris Melanosis

Spontaneous iris melanosis is usually a condition affecting one (but may affect both) eyes of cats. It starts out as small pigmented areas on the iris that eventually spread and cover the whole iris or large portions of it. Due to the possibility of iris pigmentation from uveitis and from melanoma (cancer) it is important to have your vet check the eye periodically. It is usually OK just to make sure this gets done on the yearly physical exam visits but if there are any obvious changes like a visible tumor (a lump or noticeable thickening of the iris) or clouding of the eye it is best to get it checked immediately.