Veterinary ophthalmologists treat eye disorders in many different species, from dogs, cats, and horses, to wildlife and zoo animals. Although all species have eye similarities, each has a slightly different eye structure and function that leads to unique, species-specific problems. Our Veterinary Vision Center team is skilled in treating many species, including our feline friends. Here is an overview of the most common eye conditions in cats.
#1: Feline ocular herpesvirus
Herpesvirus is an extremely common infection that most cats acquire during kittenhood. Like other herpesviruses, such as the human cold sore, the virus can remain dormant in an infected cat’s body for life. At times, the virus may reactivate, especially during stress or illness. Some cats always have low-grade infection signs, others have flare-ups a few times per year, and still others never have a recurrence.
Herpesvirus infection signs include sneezing, runny nose, nasal discharge, eye redness, eye tearing, and squinting. Most herpes-related eye problems, including conjunctivitis and corneal ulcers, become a chronic or recurrent problem. Treatments for affected cats may include antibiotic or antiviral eye drops, anti-inflammatory eye drops, or oral medications.
#2: Corneal sequestrum in cats
A corneal sequestrum is an isolated, dead area deep in the corneal layers that can be seen as a black or brown spot on the clear front eye portion. Sequestrums aren’t completely understood but are thought to result from chronic irritation, herpesvirus infection, or corneal ulcers. This condition can be painful for some cats, depending on their individual sensitivity and whether the top corneal layer is actively ulcerated.
A sequestrum may be treated with a wait-and-see approach that allows the body to slough off the dead area on its own, or surgery to remove the dead area. Surgery is typically recommended for cats who are significantly uncomfortable or who show no progress after several months of monitoring.
#3: Uveitis in cats
Uveitis is a general term describing inflammation inside the eye that may cause redness, squinting, or color changes. This condition is often caused by an underlying infection, such as toxoplasmosis, feline infectious peritonitis, feline immunodeficiency virus (FIV), or feline leukemia virus (FeLV). Sometimes, the condition is because of cancer or an immune system problem. Finding and treating the underlying cause is important to prevent permanent eye damage and vision loss.
#4: Eyelid disorders in cats
While eyelid conditions are more common in dogs, some cats are born with eyelids that roll inward (i.e., entropion) and their eyelashes rub on and irritate the eye. Maine Coons may be predisposed to developing entropion. Occasionally, kittens are born with eyelid portions missing, a condition called eyelid agenesis. Both conditions require corrective surgery to prevent serious, long-term damage to vision and eye health. Severe eyelid agenesis may require several major reconstructive surgeries to achieve a functional eyelid.
#5: Retinal detachment in cats
Senior cats are prone to retinal damage and retinal detachments, which typically occur secondary to high blood pressure and are a common hyperthyroidism and kidney disease complication. The increased pressure causes the retina’s blood vessels to bleed, pushing them from the back of the eye. Retinal detachments can cause sudden blindness, which is typically permanent. Treating high blood pressure with oral medications and addressing underlying diseases is important for the cat’s overall health, and the retina may partially reattach, but vision is unlikely to return.
#6: Iris melanosis and melanoma in cats
Iris melanosis causes benign, flat, light brown spots on the colored eye portion surrounding the pupil opening (i.e., the iris) that typically appear and progress slowly, gradually increasing in size or number over several years. Eventually, the spots can become raised and turn a deeper brown color and may change the iris muscle’s shape or function. The spots are then considered melanomas, which can spread to other body areas.
Some cats develop melanosis, but never progress to melanoma, and distinguishing between the two and determining when treatment is required can be difficult. A biopsy of the eye is not possible, so a veterinary ophthalmologist must closely monitor the lesions and recommend eye removal when they progress to a point of concern.
Cats are skilled at hiding illness signs and may continue to act normally, despite considerable eye irritation, discomfort, or pain. Schedule a visit with your primary veterinarian or our Veterinary Vision Center team if your cat displays any eye disease signs, or you notice any other changes to their eye appearance or comfort.