I don't want to alarm you, but some years ago I had a cat who at around 12
years of age began to develop noticeable brown spots in the irises of his
yellow eyes.  He also developed a kind of tic... i.e. a twitching movement
of his head which would occur intermittently.  In all other ways he was
healthy, happy and active.

I have a friend who is a vet and one day I pointed out the spots in my cat's
eyes.  She had recently been to a Vet's conference dealing with animal's
eyes and she said that sometimes the brown spots can be caused by melanoma
(a particularly virulent and potentially deadly cancer).  She asked me to
take some photographs of my cat's eyes and they were sent by email to a
veterinary research university, however a definite diagnoses could not be
made.

As my cat was otherwise in good health, and by this stage had reached 13
years of age, we thought it best to let things be.  However, about 6 months
later my cat had to go in to have his teeth cleaned.  This is done under a
general anaesthetic.  Unfortunately my cat passed away, while in recovery
from the anaesthetic.  He had come safely through the procedure and was
checked every 10 minutes or so while recovering from the anaesthetic.  When
the Vet nurse went to check on him for the 3rd time, she found him in a
distorted position, as if he had had a fit or something.

Prior to this I had never heard of melanoma appearing in the eyes!!  Here in
Australia we have a high rate of skin cancer due to the ferocity of our
summer sun, and people with pets who have pink noses & ears are advised to
always apply sun screen to their pet's vulnerable parts, as a precaution
against skin cancer.

~Roberta~