In dogs, there is a primary form and a secondary form of glaucoma. The primary form is an inherited disorder. This means that there are some specific dog breeds who are more likely to develop this condition, even at an early age. The secondary form of glaucoma in dogs instead mostly derives from an underlying eye condition such as uveitits, cataracts or retinal detachment.
A Lesson in Anatomy
In order to better understand the dynamics that take place in dog glaucoma, it helps to have a better grip on the anatomy of a dog's eye.
Usually, a dog's eye presents as a normally shaped structure that appears healthy and with tissues of a normal color. This is the combination of various well functioning mechanisms that ensure vision.
In a normal eye, for instance, special fluids ensure that the dog's eye is nourished and maintains its typical shape.
In order for these fluids to work well, they should be produced and drained efficiently. However, sometimes things may go wrong and this is where secondary glaucoma in dogs sets in.
Causes of Secondary Glaucoma
In secondary glaucoma, the dog's eye drainage system no longer operates as it is supposed to because of an underlying eye condition. The eye drainage system becomes clogged, and regardless, fluids are still being produced. When this happens, more fluids are being produced than being removed causing a a cascading chain of events and problems.
Excess fluids in the dog's eye cause increased pressure in the eye. Affected eyes therefore, will tend to stretch and enlarge. The result is ultimately great damage that leads to permanent blindness. For this reason, owners suspecting signs of glaucoma in their dog should take immediate action and have their dog's eyes seen by a veterinarian or better, an ophthalmologist specialist right away.
Symptoms of Glaucoma in Dogs
One of the biggest problems with glaucoma is that it is often misleading. Many dogs may have vision loss in one eye, but they may effectively compensate with the other, therefore, owners may not be able to recognize early warning signs.
Following are some symptoms which attentive owners may be able to detect, and that warrant an immediate veterinary appointment.
• Reddened, blood shot eye
• Ocular Pain
• Loss of Vision
• Bumping into Furniture
• Enlarged Eye
Diagnosis of Secondary Glaucoma in Dogs
The best way to diagnose secondary glaucoma in dogs is by having the dog undergo an ocular pressure reading. This test is known as 'tonometry'. Generally, a normal pressure reading in dogs with healthy eyes will give a reading between 10 and 20 mmHg. However, dogs with glaucoma may record readings from 45 to even 65 mmHg. The procedure is painless and does not require general anesthesia.
Treatment of Glaucoma in Dogs
Temporary management involves the use of eye drops and medications that either focus on reducing the amount of fluids the eye produces or that attempt to increase the drainage. In some cases, gentamycin is injected in the eye for the purpose of destroying the cells responsible for producing fluids. In order to permanently treat glaucoma, if vision is still retained, surgery is the ultimate treatment option.
In this surgery, the eye's cells that produce fluids are destroyed and an artificial drainage implant is inserted. Dogs that have lost vision, unfortunately will not regain it, and enucleation (surgical procedure to remove the eye) may be recommended. Owners that are uncomfortable with having a dog with no eye, may opt to have a prosthetic eye inserted.
- Flickr Creative Comons, Dog with bulging and clouded right eye, by Pete - Flickr: Crazy Eye, Dog, CC BY-SA 2.0