Glaucoma in Cats: Causes, Symptoms & Treatment Guide

Glaucoma in cats is a serious and potentially blinding eye condition caused by increased pressure within the eye due to impaired drainage of the aqueous humour. This fluid normally nourishes the eye and maintains its shape, but when drainage is blocked, pressure builds up, damaging the optic nerve. Early recognition of glaucoma's signs and prompt treatment are essential to preserving your cat’s vision and comfort.

Understanding Glaucoma in Cats

Glaucoma results from elevated intraocular pressure (IOP) that damages the optic nerve, leading to irreversible vision loss if untreated. In cats, glaucoma is mostly a secondary condition, arising from other eye diseases or injuries that block fluid drainage, though some breeds, like Burmese and Siamese, can have a primary (inherited) form due to anatomical abnormalities.

Secondary glaucoma can result from issues like uveitis (inflammation), lens luxation (dislocation), eye tumours, bleeding inside the eye, or trauma. These factors impair normal eye fluid drainage, causing pressure buildup.

How Glaucoma Develops

1. Fluid Production and Drainage: The eye produces aqueous humour; this fluid nourishes internal structures and exits through drainage pathways near the iris.
2. Impeded Drainage: Inflammation, debris, tumours, or lens displacement can block drainage angles. This causes fluid to accumulate.
3. Increased Pressure: The trapped fluid raises intraocular pressure, compressing the optic nerve and eye tissues.
4. Progressive Damage: Without treatment, nerve damage worsens, leading to vision loss and pain.

Recognising Symptoms of Glaucoma in Your Cat

Feline glaucoma often develops slowly and symptoms can be subtle, making regular vet checks vital. Common signs include:

• Gradual loss of vision, sometimes noticed when your cat bumps into objects
• Enlarged or bulging eyeball (buphthalmos), which may cause inability to fully close the eye
• Cloudy or bluish appearance of the cornea due to fluid build-up
• Redness of the eye or blood vessels becoming more prominent
• Dilated or unresponsive pupil with poor light reflex
• Excessive blinking or squinting
• Lethargy, reduced appetite or unusual head pressing (if pain occurs)
• Secondary signs such as debris within the eye or iris adhesion to the cornea

Diagnosis: What to Expect at the Vet

If you suspect glaucoma, your cat should be seen urgently by a vet. Diagnosis involves:

1. Full Eye Examination: The vet will evaluate eye appearance and behaviour.
2. Measuring Intraocular Pressure: Using a tonometer such as a Tonopen or Tonovet to accurately assess eye pressure.
3. Assessing Underlying Causes: Your vet may check for signs of uveitis, tumours, lens displacement, or trauma.
4. Referral: Advanced cases may require a veterinary ophthalmologist for specialised tests.

Treatment Options and Prognosis

The goals of treatment are to reduce eye pressure, alleviate pain, and try to save or preserve any remaining vision. Options include:

• Medications: Eye drops and sometimes oral drugs to lower intraocular pressure and manage inflammation.
• Surgery: Procedures may remove fluid or use techniques like cyclocryotherapy to reduce fluid production.
• Enucleation: If the eye is blind and painful, surgical removal can improve quality of life, allowing your cat to adapt to one eye.

Prompt treatment improves outcomes, but late diagnosis often leads to irreversible vision loss. Cats tolerate frequent eye treatments less well than dogs, so close collaboration with your vet is important.

Preventing and Managing Glaucoma

While primary glaucoma is largely genetic and cannot be prevented, secondary glaucoma can sometimes be delayed or avoided by:

• Managing and promptly treating eye infections or inflammations like uveitis.
• Regular veterinary check-ups for early detection of eye problems.
• Avoiding eye trauma where possible.
• Monitoring cats with known risk factors closely.

When to Seek Veterinary Advice

If you notice any unusual eye symptoms or vision changes in your cat, do not delay veterinary consultation. Early intervention gives your cat the best chance of retaining comfortable vision and quality of life.

Glaucoma in cats is a complex condition requiring compassionate care and professional management. With awareness and prompt action, many cats can continue to live happily with appropriate treatment.