Canine glaucoma occurs when there is increased pressure within the eye. This pressure is the result of a build-up of aqueous humor, an intraocular fluid. In healthy dogs, this fluid drains through a circular filter where the white sclera and clear cornea meet; this junction is known as the iridocorneal angle. However, in a dog with glaucoma, the filter has an abnormality that is blocking the flow of the fluid, thus causing a build-up of the fluid.
There are several causes for canine glaucoma:
- Intraocular tumors left untreated lead to glaucoma.
- Some dogs are born with abnormal filters that leave them prone to inherited glaucoma in both eyes.
- Certain breeds, such as Chows, have a genetic predisposition to developing displaced lenses. When the lenses are displaced, they block the filter and stop the flow of fluid.
- Dogs that develop inflammation in their eyes are at risk of their filters becoming clogged with inflammatory cells.
If glaucoma is left untreated it will lead to blindness. If you feel your dog has glaucoma, please keep reading.
There are often no symptoms; especially in the first stages of the disease. For this reason, many times glaucoma goes unnoticed and the dog eventually loses its sight. This is why a regular eye-check up by a veterinarian is very important for prompt, early treatment of the glaucoma. In later stages, there can be symptoms such as:
- Rubbing of the eyes, especially if the glaucoma is painful
- Clouded in appearance
- Appear to be slightly sunken into the skull
Eye exams are the only positive way of diagnosing glaucoma. Veterinarians use three methods to diagnose the disease:
- Ophthalmoscopy – A procedure used to evaluate the optic nerves and retina.
- Tonometry – A procedure that measures the IOP with the use of special tool.
- Gonioscopy – A procedure examining the angle of the anterior chamber.
Currently, there are several methods to correcting glaucoma in dogs. The procedure used depends on the severity and underlying cause of the glaucoma. Unfortunately there is no way to regain lost vision for your pet, but if treatment is available, it could be one of the following methods:
- Laser Surgery – Laser surgery is considered the most effective long term method for managing glaucoma. This surgery is used to selectively destroy the ciliary body and tissue to reduce the production of the aqueous fluid. This method is sometimes used in junction with shunts.
- Valved Shunts and other implants – Shunts or other implants are usually used following other failed treatment methods. These devices are used to control the flow and storage of the fluid.
- Enucleation – This method requires removal of the eyeball and is generally reserved for patients in the final stages of glaucoma.