Glaucoma in Dogs - Increased Pressure in the Eye
Glaucoma in Dogs - Increased Pressure in the Eye
Important beforehand: Fidello is not a veterinarian. This page is meant to inform you and does not provide a diagnosis. Are you unsure about your dog's health, or do you recognise the signs described below? Always contact a veterinarian. If you suspect acute glaucoma - think of a suddenly red, painful, noticeably dull or bulging eye - go straight to a veterinarian or veterinary emergency clinic: with this condition, a delay of just a few hours can already lead to permanent loss of vision.
Glaucoma is an eye condition in which the pressure inside the eye rises too high. That increased pressure can damage the optic nerve and the retina and, if left untreated, lead to blindness. In dogs, glaucoma can develop either gradually or suddenly and severely, and that difference determines how much urgency is needed.
What is glaucoma?
In a healthy eye, a small amount of fluid (aqueous humour) is constantly produced and drained again through an outflow system, keeping the pressure inside the eye stable. With glaucoma, that drainage becomes wholly or partly blocked, so the fluid builds up and the pressure inside the eye rises. Veterinarians distinguish between primary glaucoma, where the eye's drainage angle is itself too narrow or abnormally formed, and secondary glaucoma, where the raised pressure results from another eye condition, such as inflammation inside the eye, a displaced lens, a tumour, or scarring after an earlier eye injury.
Which dogs are at risk?
Primary glaucoma is reported more often in certain breeds, which points to a hereditary tendency towards a too-narrow drainage angle. Breeds mentioned more frequently in the literature include the Cocker Spaniel, the Basset Hound, the Beagle, the Akita, the Chow Chow, the Samoyed, the Bouvier des Flandres, the Shih Tzu, and the Shar Pei. A hereditary tendency does not mean a dog of such a breed will definitely develop glaucoma, and dogs without an increased breed risk can also develop secondary glaucoma as a result of another eye condition or an injury. With primary glaucoma, the condition often appears first in one eye, while the other eye carries a higher risk of developing it later as well.
Symptoms
Early signs can be subtle: a slightly pink to red eye, mild cloudiness or a bluish haze on the cornea, squinting, blinking more than usual, or a dog pawing at the eye or rubbing its head against furniture or the floor. Signs that call for urgency are: a suddenly clearly red, noticeably bulging or protruding eye, a large pupil that reacts little or not at all to light, visible pain (withdrawing, reduced appetite, whimpering), or a sudden decline in vision - for example, bumping into things. With long-standing, untreated or chronic glaucoma, the eye itself can become visibly larger (enlargement of the eyeball).
When to see a veterinarian?
If in doubt, always contact a veterinarian, even for mild or fluctuating signs such as slight redness or squinting. With a suddenly red, painful, bulging eye or a clearly reduced ability to see, no waiting time is justified: this calls for an emergency appointment with a veterinarian or veterinary emergency clinic, preferably that same day. If glaucoma has already been diagnosed in one of your dog's eyes, it is also wise to discuss with your veterinarian how often the other eye should be checked.
How is it diagnosed?
A veterinarian can measure the pressure inside the eye with a tonometer, a small instrument that determines eye pressure non-invasively. When pressure is raised, further examination often follows, such as an assessment of the eye's drainage angle (gonioscopy) and a general eye examination to establish whether primary glaucoma or an underlying cause is involved. In case of doubt or a more complex picture, referral to a veterinary eye specialist is common. This page cannot determine whether your dog has glaucoma or how severe it is; only a veterinarian can assess that after examination.
Treatment in outline
Treatment of glaucoma is aimed, first and foremost, at lowering eye pressure quickly to reduce pain and limit further damage. This is usually done with eye drops that reduce the production of aqueous humour or improve its drainage. With secondary glaucoma, the underlying cause is also treated where possible. When medication has insufficient effect, the pressure remains difficult to control, or the eye is already blind and painful, a veterinarian may discuss a surgical procedure, ranging from a procedure that further lowers pressure to, in severe and painful cases, removal of the eye to make the dog pain-free. Which approach is appropriate depends on the cause, the severity, and the duration of the symptoms, and is always determined by the treating veterinarian. Vision that has already been lost usually does not return with treatment; the goal of treatment then is mainly pain relief and protecting the other eye.
What you can do yourself
In breeds with an increased risk, watch consciously for early signs such as redness, squinting, or excessive blinking, and do not wait if in doubt. Follow a prescribed drop treatment precisely according to your veterinarian's schedule, even if the eye looks calmer, because pressure can rise again without visible signs. Prevent your dog from scratching or rubbing an eye that looks painful or inflamed, and use a protective collar if needed, in consultation with your veterinarian. None of this replaces veterinary guidance.
Prevention and responsible breeding
Because primary glaucoma has a hereditary component in a number of at-risk breeds, part of the prevention lies in responsible breeding: regular ophthalmic screening of breeding animals from at-risk breeds, and restraint in breeding from animals in which glaucoma or a markedly narrowed drainage angle has been found. For owners of a dog from an at-risk breed, periodic eye-pressure checks during the annual veterinary check-up can help detect a beginning rise in pressure early, before irreversible damage occurs.
Living with glaucoma
A dog diagnosed with glaucoma in one eye can often still function well with the other eye, although lifelong monitoring of that eye remains important. A dog that has become blind in one or both eyes also usually adapts well in practice to a familiar environment and, with the help of smell, hearing, and a consistent layout of house and garden, can maintain a good quality of life. Regular check-ups and consistently keeping up any drop treatment remain the most important factors in safeguarding your dog's comfort in the longer term.
Frequently asked questions
Is glaucoma in dogs always an emergency?
Not every form progresses just as severely, but a suddenly red, bulging, or painful eye with reduced vision should always be treated as an emergency, because damage can become irreversible within hours.
Can a dog with glaucoma see normally again?
Vision that has already been lost usually does not return; treatment is then mainly aimed at reducing pain and protecting the other eye.
If one eye is affected, will the other eye develop glaucoma too?
With primary glaucoma there is an increased risk that the other eye will develop it over time as well, which makes regular monitoring important; this does not happen in every dog.
Can I recognise glaucoma in my dog myself?
You may notice signs such as redness, cloudiness, or pain, but only a veterinarian with a tonometer can reliably measure the eye pressure itself.
Conclusion
Glaucoma is a rise in pressure inside the eye that, whether primarily through a hereditary tendency or secondarily through another eye condition, can damage the optic nerve and lead to blindness. Certain breeds carry a higher risk, but for every dog the same rule applies: a suddenly red, bulging, or painful eye with reduced vision is an emergency in which prompt veterinary help can make the difference between preserving and losing vision. Timely recognition, regular checks in at-risk breeds, and consistently following a prescribed treatment give a dog with glaucoma the best chance of a comfortable life.
Finally
Finally: this article does not replace a visit to the veterinarian. Fidello does not provide diagnoses and does not prescribe treatments. If in doubt, or in case of persistent symptoms or acute signs, a veterinarian is always the right next step.