Common eye issues that we will see in cats include corneal trauma, conjunctivitis, anterior uveitis, blepharitis, chorioretinits, melanosis, and eye drainage. What are all of these? Keep reading.
Corneal trauma. This includes scratches and ulcers on the eye. Scratches are most often caused by a fight or rough play with another cat. Ulcers can be caused by a variety of causes, from herpes virus, chlamydia, mycoplasma, trauma such as eyelashes rubbing on the surface of the eye, decrease in tear production, or inability to fully close the eye due to trauma. With minor scratches and ulcers, we can usually treat these with eye drops. For more advanced trauma, we may need to treat with specific systemic antibiotics or antivirals, or with a surgical procedure called a third eyelid flap where the third eyelid is actually sewn shut over the eye to bring healing blood supply to the surface of the eye.
Conjunctivitis. This is when the third eyelid becomes red and inflamed. This most commonly happens as a result of an upper respiratory infection such as herpes virus, calici virus, chlamydia, mycoplasma, or secondary to corneal trauma. We will usually treat this with eye drops, but we may also need to treat the upper respiratory infection as well.
Anterior uveitis. This means that there are red or white blood cells in the front chamber of the eye, giving a reddish or cloudy appearance. This can be a result of more severe corneal trauma, but this can also be an indication of a major systemic illness. This is not a good thing, and we generally need to treat the underlying disease process to treat the anterior uveitis.
Blepharitis. This is when not only is conjunctivitis present, but the upper and lower eyelids are also inflamed and swollen to the point that you may not be able to see your cat's eye. This can be a result of corneal trauma or secondary to an upper respiratory infection. This usually happens when conjunctivitis goes untreated and progresses to blepharitis.
Chorioretinitis. This is not something that you can see with the naked eye. This is something that we vets can find when we are looking through an ophthalmoscope into the back of the eye at the retina. This looks kind of like fluffy clouds or spots on your cat's retina. This is also not a good thing, and usually indicates a significant systemic inflammatory disease. We need to find the source of the disease, and treat it if treatable to treat the chorioretinitis.
Melanosis. This is when you start to notice little brown spots in your cat's iris that seem to be growing. If the brown spots grow to a point that covers less than 50% of the iris and then stop, then they are probably not a concern. Melanosis is a benign disease process. But if they keep growing until your cat's iris is turning almost completely brown, this could be a progression from benign melanosis to malignant melanoma, and should be checked out by a veterinary ophthalmologist.
Eye drainage. So your cat has crusty or gooey eye drainage coming from one or both of their eyes, and this hasn't happened before. This could mean something as simple as your cat's tear ducts have become blocked (common in brachycephalic breeds like Persians), or it could mean that your cat has some mild irritation to their eye, either corneal trauma, or a mild upper respiratory infection. This is not a huge thing, but it could potentially get worse, so probably a good idea to have it checked out by a vet.