By Dial A Vet Veterinary Team
Acute glaucoma is one of the few eye problems where hours genuinely count. When fluid cannot drain from the eye, pressure builds quickly, crushing the nerve cells at the back of the eye. Vision loss can become permanent within a day or two, and the eye is intensely painful, often described by people with glaucoma as a severe headache. If your dog has a red, cloudy, painful eye, it should be checked by a vet the same day.
Key takeaways
- Glaucoma is raised pressure inside the eye, which damages the optic nerve and retina.
- Signs include a red eye, a cloudy or bluish cornea, squinting, a dilated pupil and sudden vision loss.
- Primary glaucoma is inherited and common in breeds such as Cocker Spaniels, Basset Hounds, Shiba Inus, Siberian Huskies and Chow Chows.
- Secondary glaucoma follows other eye problems, such as lens displacement, inflammation or tumours.
- Acute glaucoma needs emergency treatment. Lifelong management is often needed.
What happens in glaucoma
The front of the eye constantly makes a clear fluid that drains out through a filtration angle. If drainage is blocked, fluid accumulates and pressure rises. Raised pressure damages the retina and optic nerve and stretches the eye, which can eventually enlarge it.
Primary glaucoma is due to an inherited abnormality of the drainage angle. It often affects one eye first, and the other eye is at high risk of following.
Secondary glaucoma develops because something else blocks drainage, such as inflammation inside the eye (uveitis), a displaced lens, bleeding, or a tumour.
Signs to watch for
- A red, bloodshot white of the eye
- A cloudy or blue-tinged cornea
- Squinting, rubbing or holding the eye shut
- A pupil that is larger than the other one, or does not shrink in bright light
- Watery discharge
- Sudden bumping into things, or reluctance to move in unfamiliar spaces
- Lethargy, poor appetite, or reluctance to be touched around the head
- In long-standing cases, an eye that looks larger than the other
When to see a vet
Emergency now (same day, as soon as possible): a red, cloudy, painful eye, a suddenly dilated pupil, or sudden loss of vision. Do not wait to see if it improves overnight.
Same day: any squinting, eye redness or cloudiness in a breed at risk of glaucoma, or in a dog that has already had glaucoma in one eye.
Book a check: breed screening, or if you notice subtle changes such as a slightly different pupil size.
How vets diagnose glaucoma
Your vet will measure the pressure inside each eye using a tonometer, a quick and painless test after numbing drops. They will also check vision, pupil responses and the structures inside the eye. A referral to a veterinary ophthalmologist is common, where the drainage angle can be assessed with special lenses (gonioscopy) and the retina examined in detail. Ultrasound may be used if the eye is too cloudy to see inside.
Treatment overview
The aims are to lower pressure quickly, relieve pain and, if possible, save vision.
- Emergency medical treatment: prescription eye drops and sometimes other medicines are used to reduce fluid production and improve drainage. Your vet chooses these based on the type of glaucoma.
- Ongoing medication: many dogs need daily eye drops for life, with regular pressure checks.
- Surgery: specialists may offer procedures to reduce fluid production or create new drainage, mainly for eyes that still have vision.
- Comfort procedures: for blind, painful eyes, removing the eye (enucleation) or placing a prosthesis inside the eye can end chronic pain. Many dogs are noticeably happier afterwards.
- Protecting the other eye: with primary glaucoma, preventive drops may be prescribed for the unaffected eye.
Living with glaucoma
Dogs adapt remarkably well to vision loss, especially when it comes on gradually. Keep furniture in familiar places, use baby gates at stairs, and talk to your dog as you approach. Our article on signs a dog is losing vision has practical tips. Keep up regular pressure checks and give medications exactly as prescribed.
Prevention
Primary glaucoma cannot be prevented, but its impact can be reduced:
- Ask breeders about eye screening and family history in high-risk breeds.
- Have at-risk breeds checked regularly by your vet, with pressure readings if advised.
- Act fast on any red, cloudy or painful eye.
- Use a harness rather than a neck collar for dogs with glaucoma, as pulling on a collar can raise eye pressure.
FAQ
Is glaucoma painful for dogs?
Yes, often very painful, even when dogs do not show it obviously. Pain control is a major part of treatment.
Can glaucoma be cured?
It usually cannot be cured, but it can be managed. The goal is a comfortable eye, ideally with vision preserved.
Will my dog lose the other eye too?
In primary glaucoma, the second eye is at high risk. Preventive treatment and monitoring can delay or reduce this.
Is glaucoma the same as cataracts?
No. Cataracts cloud the lens; glaucoma is raised pressure. They can be linked, though. See our article on cataracts in dogs.
Talk with a vet
If your dog's eye looks red, cloudy or painful, a Dial A Vet veterinarian can help you judge urgency and what to tell your clinic. Consult Dial A Vet. A suspected glaucoma attack is an emergency that needs an in-person vet as soon as possible.
References
- Merck Veterinary Manual: Glaucoma in animals
- American College of Veterinary Ophthalmologists (ACVO): Glaucoma owner information
- Gelatt, Veterinary Ophthalmology (textbook)
- Australian and New Zealand College of Veterinary Scientists, Ophthalmology Chapter: Owner resources
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.
