Pets get Glaucoma, too

Dogs and cats have more rods but less cones in their eyes compared to humans. As a result, they are better able to see in the dark and better at noticing even subtle movements, but they do not see colors as well as humans. Despite these differences, they are still at risk for similar diseases, such as glaucoma and cataracts.

Glaucoma is when the pressure in the eye is elevated. This can cause pain and blindness. Glaucoma is typically separated into two categories: primary and secondary. Primary glaucoma is when an inherited or congenital anatomical problem affects how fluid drains from the eye, leading to a buildup of fluid, and therefore pressure. This often affects one eye at a time, but typically both eyes do become affected at some point. Secondary glaucoma is the consequence of another disease process. Some examples include damage to the eye, infections, tumors, and diseases that cause inflammation and bleeding in the body. Glaucoma occurs more frequently in dogs than in cats, but overall is not a common condition, affecting less than 1% of both species. Primary glaucoma occurs more often in dogs, whereas cats are more likely to have secondary glaucoma. Certain breeds of dogs and cats can be predisposed to primary glaucoma.

Glaucoma in pets is typically very painful as the pressures in the eye can rapidly increase to values higher than in people. As the pressure rises, the eye can physically stretch, causing extreme pain and blindness. This can happen rapidly or sometimes overtime. The eye can look relatively normal in mild and/or early causes of glaucoma. If blindness does occur in just one eye, the pet can still act normally, making the diagnosis delayed. Some signs that can be noticed at home include squinting, bloodshot eye, cloudy bluish eye, dilated pupil, and bulging eye. Sometimes pets can rub their eyes or flinch when being petted. They can also display lethargy and inappetence because of the pain.

If glaucoma is suspected, the pressure in the eyes can be measured and compared to each other as well as the normal range for the species. Medications, similar to those used in human glaucoma, can be considered, and require consistent continuous treatment. It is important to note that humans should not take it upon themselves to use their own medications in their pets as it depends on the type/cause of glaucoma - some medications can actually be dangerous if used. Also, some medications are riskier depending on the species (dog vs. cat). Medications used are topical – applying directly to the eyes, but sometimes oral pain medications are also used to help provide some comfort.

Other diagnostics may be considered, and a referral to a veterinary ophthalmologist may be discussed, to determine any underlying conditions causing glaucoma. Ophthalmologists can also perform surgeries to alleviate glaucoma. Sometimes the eye does not respond to medications or surgeries, or these options are not feasible for some pets and their owners for various reasons. In these cases, removing the eye is considered – often the eye is permanently non-visual and extremely painful and removing the eye relieves the pet.

The prognosis typically depends on the type of glaucoma, but glaucoma often requires constant long term treatment to keep it under control.