Iris melanoma

Iris melanomas are tumors that appear as darker pigment areas on the surface of the iris (colored part of the eye). They are most common in cats, especially older cats, but may also be seen in dogs.
These tumors can be both benign (don't spread) or malignant (spread to other parts of the body). This can only be determined by collecting a sample via a fine needle and analyzing the cells. If a tumor is categorized as malignant or has become quite large then the eye should be removed. By the time a diagnosis is made the tumor may have already spread, however there is no definitive way to tell unless obvious lesions have appeared elsewhere. Secondary problems in the eye including glaucoma and uvetitis are common.
Cases that involve benign, or small superficial tumors have a number of treatment options available. A laser can be used to destroy the tumor cells, surgical removal of the affected area can be performed, or the eye can be completely removed. Eye saving surgery does involve a risk of the tumor returning and should be followed with regular checks every 6 months.