What Is Glaucoma?
Glaucoma is a group of conditions in which pressure inside the eye (intraocular pressure) rises high enough to damage the optic nerve and threaten vision. In dogs and cats, aqueous humor (the clear fluid inside the front of the eye) cannot drain properly, so pressure climbs. Glaucoma is painful and can progress from subtle redness to an emergency that blinds an eye within hours to days.
Veterinarians often describe primary glaucoma (often breed-related drainage-angle problems, especially in dogs) and secondary glaucoma (pressure rise caused by inflammation, lens luxation, trauma, tumors, or chronic uveitis). Cats more often develop secondary glaucoma tied to ongoing intraocular inflammation. Either way, “wait and see” is risky once pressure is high.
Why it matters
A red, cloudy, or suddenly blind eye can be glaucoma — a true ophthalmic emergency. Fast pressure checks and treatment can save remaining vision and relieve severe pain even when sight cannot be restored.
Signs Owners Notice
- Red eye, squinting, or rubbing at the face
- Cloudy or bluish cornea; a pupil that stays dilated
- Tearing, light sensitivity, or a visibly enlarged “bulging” eye in chronic cases
- Sudden vision loss (bumping into furniture, missing stairs) — sometimes owners notice blindness before redness
- Behavioral clues of pain: withdrawal, appetite drop, hiding
Chronic glaucoma can enlarge the globe over time. Acute congestive glaucoma can look dramatic overnight. Either presentation deserves same-day veterinary attention when possible.
Diagnosis and Treatment
Diagnosis centers on measuring intraocular pressure with a tonometer, examining the drainage angle and internal structures, and identifying primary vs secondary causes. Your veterinarian may refer to a veterinary ophthalmologist for gonioscopy, advanced imaging, or surgical planning.
Treatment goals are to lower pressure quickly, control pain, preserve any remaining vision, and address underlying causes:
- Emergency pressure-lowering eye drops and sometimes oral medications
- Anti-inflammatory therapy when uveitis drives secondary glaucoma
- Surgical or laser procedures in selected cases to improve outflow or reduce fluid production
- If an eye is blind and painfully unresponsive to therapy, removal (enucleation) or other comfort-focused procedures can be the kindest option
Never use leftover human eye drops without veterinary direction — some products are dangerous to pets.
Prevention and Monitoring
- Know breed risk: some dog breeds are predisposed to primary glaucoma; ask your vet about screening.
- Treat uveitis, lens problems, and eye injuries promptly so secondary glaucoma is less likely.
- If one eye has primary glaucoma, ophthalmologists often discuss prophylactic drops for the other eye.
- Keep recheck appointments for pressure monitoring — numbers can climb again after an initial win.
When to see a vet
Treat a suddenly red, cloudy, painful, or blind eye as urgent — ideally the same day. Emergency care is warranted for severe pain, rapid vision loss, or a rock-hard-feeling globe. Do not wait overnight “to see if it clears.”
Key Takeaways
- Glaucoma means damaging high eye pressure — painful and vision-threatening in dogs and cats.
- Primary (often breed-related) and secondary (inflammation/trauma/lens) forms both need fast care.
- Tonometry, prescription pressure control, and sometimes surgery or eye removal for comfort are the practical toolkit.
FAQ
Can glaucoma be cured with one bottle of drops?
Usually not. Many pets need ongoing medication, monitoring, and sometimes procedures. Skipping drops can let pressure rebound.
If my dog is already blind in that eye, why treat?
Blind glaucomatous eyes can still hurt. Pressure control or surgical comfort options protect quality of life.
Is glaucoma contagious between pets?
No. It is a pressure/drainage problem, not an infection you catch from another animal — though shared households may share breed risk if related.