It’s World Glaucoma Week from the 10th-16th March. Glaucoma is a leading cause of blindness in people and it can also affect our pets. Glaucoma is a condition where the pressure inside the eye builds up. It is extremely painful and can lead to permanent blindness.
Glaucoma can be primary (it comes on all by itself), or secondary (where it is related to another condition of the eye).
Primary glaucoma is caused by a genetic problem with the drainage of fluid inside the eye. There are two types of primary glaucoma.
- Primary open-angle glaucoma affects breeds such as the Petit Basset Griffon Vendeen, Basset Hound and Shar Pei. DNA testing is available and all breeding stock should be tested. In dogs which carry the mutation, annual eye pressure checks on dogs over 3 years of age should be performed.
- Primary closed-angle glaucoma is more common and affects many different breeds of dog. Breeding dogs should be tested regularly by a specialist using a technique called gonioscopy. By not breeding from affected dogs, it is hoped that the prevalence of glaucoma will be reduced. This type of glaucoma often comes on very suddenly (even overnight), is very painful and can lead to sudden and permanent blindness. At risk breeds include:
- Siberian Husky
- Flat-coat Retriever
- Basset Hound
- Springer Spaniels
- American Cocker Spaniel
- Spanish Water Dog
Secondary glaucoma happens due to another issue within the eye such as lens luxation (where the lens slips out of place within the eye), uveitis (inflammation inside the eye), a tumour, or an injury to the eye.
What are the signs of glaucoma?
Signs of glaucoma include:
- Redness of the eye
- Bulging of the eye
- Enlargement of the pupil (although it can sometimes become smaller)
- Cloudy appearance of the eye
If you notice any of these signs, you should contact your vet immediately. Delayed treatment can lead to permanent sight loss.
How is glaucoma diagnosed?
To diagnose glaucoma, your vet will use a tonometer. This is a special instrument which measures the pressure inside the eye. Depending on the type used, the eye may need to be numbed first with some local anaesthetic drops. A normal pressure inside the eye is 10-25mmHg. In glaucoma, this often goes above 40mmHg.
How is glaucoma treated?
Glaucoma is an emergency condition. If left untreated, it will cause severe pain and permanent blindness. Early treatment provides the best chance of saving sight.
Initial treatment involves drops to improve drainage in the eye and reduce the pressure. Referral to a specialist ophthalmologist is highly recommended for the best possible outcome. Regular testing of the pressure inside the eye is really important to ensure the problem is being treated appropriately.
If treatment is unsuccessful and the dog is blind, surgical removal of the eye is the best option. Although this sounds brutal, it will remove the dog of a painful, useless eye and drastically improve their quality of life.
There is a high risk of the other eye becoming affected, depending on the cause of the problem, so preventative treatment may be required, this will usually involve eye drops and regular monitoring.