What is Glaucoma in Cats? Symptoms and Treatment
26 April, 2018
Glaucoma in cats is a condition when there is high pressure in the eye which leads to the failure of normal fluid drainage from the eye. If this becomes chronic, the pressure against the optic nerve will eventually cause permanent damage to the optic nerve and can result in blindness. Glaucoma in cats is much more rare than in dogs and humans.
There are two types of glaucoma: primary and secondary
Determining if your cat has primary or secondary glaucoma is important because the treatment needed and the prognosis for vision is different for each type.
Primary glaucoma in most cats usually begins in one eye, but it eventually involves both eyes and leads to complete blindness. The symptoms are usually: high pressure within the eye, blinking of the eye, redness in the white of the eyes, dilated pupils and vision loss.
Secondary Glaucoma occurs when other eye diseases cause decreased fluid drainage. Common causes of secondary glaucoma are inflammation inside the eye, advanced cataracts, cancer in the eye, lens subluxation or luxation, and chronic retinal detachment. Glaucoma in cats is usually secondary to chronic inflammation of the uveal tract (uveitis), which is the pigmented, vascular part of the eye.
How do you know if your cat has glaucoma?
The only way to really know if your cat has glaucoma is to take you cat to your veterinarian who will have the intraocular pressures measured. Signs of glaucoma can include a red or bloodshot eye and/or a cloudy cornea; vision loss is also characteristic of glaucoma. However, loss of vision in one eye is often not obvious because you cat will usually compensate with the remaining eye. Eventually, the increased pressure will cause the eye to stretch and become enlarged. Unfortunately, eyes are usually permanently blind by the time they become enlarged.
Electroretinography will be also performed by the veterinary ophthalmologist to determine if the eye will remain blind despite treatment. In secondary diseases, X-rays and an ultrasound may show abnormalities within the eye.
How is glaucoma treated?
Since glaucoma occurs when fluid is not draining from the eye fast enough, the best way to treat it would be to open up the drain. Unfortunately, opening the drain and keeping it open is difficult. Therefore, many glaucoma therapies are also aimed at decreasing fluid production by the eye.
Medication for glaucoma
There are several different types of eye drops and pills that help decrease fluid production or increase fluid drainage from the eye. While these medications are helpful, they usually do not control glaucoma in long term. Consequently, they are used mostly to help prevent or delay the onset of glaucoma in the remaining visual eye, and as temporary treatment until surgery can be performed in the affected eye.
Surgery for glaucoma
The type of surgery for glaucoma depends on whether the eye still has the potential for vision. For visual eyes, intraocular pressure can be reduced by performing a cycloablation procedure and a drainage implant procedure. For permanently blind eyes, the eye can be removed with the option of placing a sterile prosthetic ball implant in the eye socket prior to skin closure, an implant placed inside the eye giving the cat a partially artificial eye.
Management of glaucoma
If the condition has been caught early enough and your veterinarian is able to manage the condition, you will need to see your veterinarian regularly to have the pressure in the eye assessed and to monitor the drug interactions. Your veterinary ophthalmologist will examine the good eye to determine its risk of also developing glaucoma. It is very common for cats with primary glaucoma to develop complications in their unaffected eye within a short time, therefore preventative therapy should be done.
Your cats can adjust to the loss of vision and live a fulfilled life
Most cats will adjust over time to the loss of their eye, especially as they may have been losing their vision over a period of time. Talk to your veterinarian about ways in which you can help your cat to transition and how you can help to make its life easier without its sight.
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