The front chamber of the eyeball is filled with a fluid, called aqueous humor. A balance between production and outflow of aqueous humor is responsible for maintaining normal eye pressures. If infection, inflammation, trauma, cancer or anatomical abnormalities, which often are determined genetically, block the normal flow of fluid out of the eyeball, eye pressures increase and glaucoma results. The disorder is diagnosed in all types of animals but most commonly affects middle-aged dogs.
Typical symptoms of glaucoma include pain, squinting and red eyes. In more advanced cases, the surface of the eye may become cloudy, they entire eyeball can appear enlarged, and permanent blindness may result. To differentiate glaucoma from other diseases (e.g., eye infections and injuries to the surface of the eye) that cause similar clinical signs, a veterinarian will thoroughly examine the eyes with an ophthalmoscope, measure eye pressures, stain the eyes' surface to look for wounds and check tear production levels.
When eye pressures rise quickly, an animal can lose sight in the affected eye within 12 to 24 hours. Therefore, call a veterinarian immediately if glaucoma is suspected. Once the patient is stabilized, many veterinarians will refer glaucoma cases to a veterinary ophthalmologist for continued care. Treatment options include topical and/or oral medications that decrease eye pressure, addressing any underlying conditions, and surgical procedures to restore the balance between aqueous humor production and drainage or to remove sightless but still painful eyes. Many patients with glaucoma require life-long treatment and monitoring.
Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008