Thank you Anne,
That is fine, its only that I am always keen to have a peek at their eyes so that I can aid you in narrowing down some causes for the discoloration you are seeing in this eye.
Now as I am sure you can appreciate, eye color isn’t something that naturally changes in adult animals. Often the colour the eye is at 3 months of age will be the color of that cat’s eye for life. Now to see changes, especially in only one eye, does raise red flags of concern here. Even if this is not bothering her, we do need to be cautious here (since often we don't see it disturbing the cat until the condition is advanced). And there can be a range of reasons for an eye to change color.
With your further information, it does not sound like we are seeing iris color change. Therefore, this would make issues like iris degeneration (though usually involving both eyes), melanosis and tumors like malignant melaomas less likely. Instead, we'd have to think about disease processes that could affect the color appearance of the eye on the whole (and make the pupil also appear discolored). In that case, we have to consider that this would be done by a discoloration of the fluid within the eye. And the most common causes of that will be hyphema (blood in the eye like the example I posted above) or uveitis.
In regards XXXXX XXXXX this is something we can suddenly see in a single eye of an elderly cat due to a rupture of blood vessels within the eye. Most commonly this will be seen secondary to high blood pressure but we can also see it with some viral dieases (ie FIP) or if there is a tumor present in the back of the eye that is eroding vessles. In this case, then cat will often not have full sight in the eye, but as the blood is absorbed (and provided the trigger doesn't cause another bleed) sight is usually restored.
Our other concern, and the one I would be most suspicious of here, is uveitis (example 1, example 2). This is a condition that causes inflammation of the uveal tract (which includes the iris and other vascular parts of the eye). It is a condition that can be caused by a range of agents. This includes trauma, bacterial infection, viral disease (ie FIV, Feline leukemia virus, FIP, feline herpes virus), parasitic infection (ie Toxoplasma), tumors (ie lymphoma, iris melanoma), and in some cases can be idiopathic (where a cause can not be determined). Often these eyes will require supportive care (ie antibiotics, anti-inflamatories) while diagnosing which of the above is triggering the signs. If not addressed, then we can see glaucoma arise and we can see blindness, corneal ulceration, and sometimes rupture of the eye.
Overall, any color change in an adult cat's eye is a worry, but to see sudden color change in the anterior part of the eye is often an even more pressing worry. So, while I do appreciate that you don't want to stress her with a vet visit, I would be very worried about the state of her eye and her health overall (since spontaneous issues from high blood pressure can cause even more serious issues in the rest of the body as well as sudden blindness). Therefore, I would advise that the best course of action here would be to consider requesting your vet do a home visit. In the UK, this is a service that is offered and an option here. This way you would avoid stressing Buddy but be able to have her eye assessed. Depending on their findings, they can provide treatment for the eye +/- her blood pressure if it is found elevated. And this way you would avoid her suffering with any progressing disease that could take aware her sight or cause her eye to deteriorate (or rupture).
Just in case you don't have a local vet, you can find one via the RCVS Register (HERE)
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best,
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