Glaucoma in cats is a condition in which the pressure inside the eye reaches abnormal levels. This increase in pressure damages the optic nerve and retina of affected cats, creating a multitude of problems.
Feline glaucoma is a progressive disease, and it can do so quickly. Without proper intervention, affected cats will lose their vision entirely. Fortunately, the condition can be managed and treated.
But before that, let’s talk about what glaucoma in cats is. In this blog, we’ll tell you everything you need to know, from the symptoms to the treatment process and prevention tips.
What Is Glaucoma in Cats?
To understand what feline glaucoma is, you must first understand a few key terms:
Aqueous Humor. The fluid inside the eyeball that circulates and maintains eye pressure.
Ciliary Body. Produces the aqueous humor and helps the lens focus on objects.
Intraocular Pressure. IOP refers to the pressure of the fluid inside the eye.
Iridocorneal Angle. The area where the iris and cornea meet, which is the primary pathway for the outflow of the aqueous humor. Also known as the drainage angle.
In normal eyes, aqueous humor is constantly being produced and drained at a steady rate. When the iridocorneal angle gets blocked or obstructed, the fluid accumulates and causes increased IOP.
This results in damage to the optic nerve and retina, ultimately leading to feline glaucoma.
What are the Types of Glaucoma in Cats?
Glaucoma comes in two types, namely:
Primary Glaucoma
This type of glaucoma in cats is considered rare as it’s caused by hereditary factors and structural abnormalities within the eye’s drainage system.
Some cats are born with narrow or poorly formed drainage angles inside the eye. This slows down the outflow and drainage of aqueous humor, allowing pressure to build up gradually over time. Cats with an increased risk of glaucoma compared to other breeds include:
Secondary Glaucoma
Secondary glaucoma in cats is a more common type, as it happens because of another underlying health or eye condition. This type often occurs later in life and can progress rapidly depending on the cause. Common factors include:
Uveitis. A painful inflammation of the middle layer of the eye. Uveitis causes swelling and protein buildup, which can result in the obstruction of the eye’s drainage angle.
Lens Dislocation. The lens, which is held together by zonules, can shift forward or backward, causing problems with the outflow of fluid.
Intraocular Tumors. Tumors can block or compress the structures that are involved in the drainage of the aqueous humor.
Eye Injuries and Intraocular Bleeding. Blunt trauma, scratches, or penetration injuries can lead to intraocular bleeding and inflammation, which can compromise the drainage system.
Advanced Cataracts. When the lens becomes clouded from advanced cataracts, this can block the normal flow of fluid within the eye, causing increased intraocular pressure.
What are the Symptoms of Glaucoma in Cats?
Glaucoma in cats often develops silently, with subtle signs that can be easily missed. These include:
Redness in the Eye. A bloodshot or visibly red eye can be one of the earliest indicators of increased pressure in the eyes. The redness can come from the dilation of the blood vessels.
Excessive Tearing or Watery Eyes. An increase in tearing can occur as the eye enlarges and tries to flush out the fluid.
Frequent Squinting or Blinking. Due to the constant discomfort, affected cats may squint or blink more frequently. Some may keep their eyes partially closed.
Cloudy or Bluish Cornea. As fluid builds up, it can cause swelling in the cornea, making it look cloudy or hazy.
Enlarged Eyeball. In advanced cases, the eyeballs may look enlarged. This occurs due to persistent pressure.
Vision Loss or Disorientation. If your cat starts bumping into objects, hesitates to enter unfamiliar spaces, or has trouble navigating, it might be losing its vision.
Unequal Pupil Size. One pupil may look larger than the other if the affected eye has increased pressure.
Behavioral Changes. Cats may appear irritated and withdrawn, while some may tend to hide or have a reduced appetite.
How Do Vets Diagnose Feline Glaucoma?
Glaucoma can’t be accurately diagnosed with just a visual inspection. The main methods for diagnosing glaucoma in cats include tonometry, gonioscopy, and ophthalmoscopy.
Tonometry allows us to measure the intraocular pressure of your cat, providing a numerical reading. This is done by applying numbing drops and gently touching the tonometer on the surface of your cat’s eye.
Normal IOP ranges from 10 to 25 mmHg. If it’s above 25 mmHg, we highly recommend starting treatment and management. Values above 40 mmHg will require urgent care and treatment to avoid permanent vision loss.
Another method we use is a gonioscopy. This is mainly used when primary glaucoma is suspected. It works by using a special lens to evaluate the shape of the eye’s drainage angle. Narrow or abnormally formed structures suggest a genetic issue.
Additionally, we can do an ophthalmoscopy to assess the optic nerve and retina for signs of damage.
What Is the Treatment for Glaucoma in Cats?
Treating glaucoma in cats focuses on lowering eye pressure, relieving pain, and preserving vision. Here are the methods we use:
Medical Treatments
Eye drops are often prescribed to reduce eye pressure, decrease fluid production, and help with fluid outflow. These may include carbonic anhydrase inhibitors, beta-blockers, and prostaglandin analogs.
Sometimes oral medications are prescribed in addition to drops, especially in more advanced cases.
Additionally, specific medications can be prescribed to treat the specific issue causing the increased pressure. These can include anti-inflammatory medications and antibiotics.
Surgery
The surgical techniques we use depend on your cat’s situation and can range from cyclodestructive to filtering procedures and enucleation.
Cyclodestructive procedures involve destroying the ciliary body. One example is cyclophotocoagulation. Here, a laser targets a part of the ciliary body, reducing fluid production, which will help lower intraocular pressure.
This is generally the treatment considered when other treatments aren’t suitable for your cat.
Filtering procedures help create new options and pathways for the fluid to drain, reducing IOP. One example is the insertion of a tiny tube in the eye. Another method is by inserting an aqueous shunt implant to increase the outflow of aqueous humor.
In some cases, enucleation, or the complete removal of the eye, may be performed to alleviate pain and manage uncontrollable pressure.
Glaucoma in Cats Prognosis
The prognosis for cats with glaucoma depends on how early it’s caught and whether it can still be managed. In many cases, the disease progresses even with steady treatment. Medication and surgery can only delay the onset of blindness.
However, if caught early, it may be possible to significantly slow down the disease, especially when IOP is well-controlled. Feline glaucoma is still a lifelong condition that requires ongoing management and monitoring.
If your cat has partial or complete blindness, it’s best to make a few home adjustments to make them more comfortable. Keep their living areas safe and use scent or texture markers in bedding, food bowls, and litter boxes.
How Is Feline Glaucoma Prevented?
While feline glaucoma is not entirely preventable, there are some ways to reduce the risk by protecting your cat against several eye problems.
For one, routine vet visits are important to detect any eye issues early on, including glaucoma and other conditions that can cause it.
Also, keep an eye out for your cat’s activity. Any injury or trauma to the eye can cause glaucoma, which is challenging to manage.
Additionally, keep your cat’s eyes clean regularly to prevent them from scratching.
“Your cat may not speak, but their eyes tell a story. Keep them healthy, and that story stays bright.”
- Dr. Nenad Misura
Conclusion
Feline glaucoma is a serious condition that requires proper attention. By keeping your cat safe and its eyes protected, you can significantly reduce the risk of glaucoma.
But while it’s not entirely preventable, there are ways to manage the condition and provide a happy life for your best friend.
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