Glaucoma - The major cause of blindness in pets
Early detection is the only way of controlling glaucoma
What is glaucoma?
Glaucoma is the leading cause of blindness in dogs and is caused by increased fluid pressure in the eye, or intraocular pressure.
The fluid inside the eyeball is called the humor. Since there are no blood vessels going to the cornea and lens of the eye, it is the job of the humor to supply them with nutrients and oxygen. There are cells called the ciliary body, that produce this fluid inside the eyeball. These fluids drain out of the eyeball where the cornea meets the iris, the iridocorneal angle.
With glaucoma, the fluid does not drain correctly from the eye, and as a result, the pressure of the humor rises. Sometimes the rise in fluid pressure can happen very quickly, in a matter of hours. Sometimes it builds slowly over time. In either case, the abnormally high pressure causes damage to the retina and the optic nerve, leading to blindness. Timely diagnosis and treatment of glaucoma can save your pet pain, suffering and possibly blindness.
Two types of glaucoma
Primary Glaucoma - is inherited. This means that some breeds of dogs and cats have physical or physiological traits that predispose them to developing glaucoma. Primary glaucoma doesn’t usually develop until a dog is 2-3 years old, or older. Glaucoma rarely occurs in both eyes at the same time and can take months or even years for the second eye to be affected.
Secondary Glaucoma - occurs when other eye diseases or injuries cause decreased fluid drainage. Some common causes of secondary glaucoma are inflammation inside the eye, bleeding in the eye, or dislocation of the lens.
Glaucoma warning signs
It is important to recognize glaucoma as early as possible. The faster treatment is started, the greater the chance of saving vision in the affected eye.
• pain – can be characterized by loss of appetite and depression, or pawing at the eye
• a dilated pupil
• cloudiness within the cornea
• red or bloodshot eye
• loss of vision
Dog and cat breeds that have a predisposition to glaucoma
Smooth Coat Fox Terrier
Wired-Hair Fox Terrier
Diagnose & Treatment
Annual screening exams are recommended, especially for those pets that have a predisposition for eye disease. Glaucoma is diagnosed by measuring the intraocular pressure with a tonometer. This is usually done with local anesthetic drops placed in your dog’s eye.
There are three goals to treatment of glaucoma, depending on the cause:
1) Reduction in the intraocular pressure
2) Reduction in the amount of aqueous humor that is produced
3) Increase in the drainage
There are several different types of eye drops and pills that help decrease fluid production or increase fluid drainage from the eye. These medications can help, but they usually do not control glaucoma for the long term. They can help prevent or delay the onset of glaucoma, and can work as a temporary treatment until surgery can be performed in the affected eye.
The choice of surgical procedures for glaucoma will depend on whether the eye can still see. For visual eyes, the goal of surgery is to decrease the production of fluid in the eye, and to improve the drainage from the eye. There are a few different methods that a veterinary ophthalmologist can use to achieve this. If the eye is irretrievably blind, it can be removed or modified with a prosthesis. In either case, your dog or cat will no longer experience the pain the glaucoma.