Glaucoma is caused by increased pressure in the eye. This is called intraocular pressure or IOP. Cells in the eye produce a clear fluid called the aqueous humor. This helps maintain the shape of the eye. The cornea and lens do not have blood vessels, so the aqueous humor brings oxygen and nutrients to the eye while taking away waste. When the aqueous humor does not drain properly, it builds up, causing IOP. The eyeball is usually strong enough to not stretch, so the internal parts of the eye tend to warp. The retina and the optic nerve are very sensitive to pressure and damage easily. This is where the problem occurs.
Types of Glaucoma
There are two types of glaucoma: primary and secondary. Primary glaucoma is usually genetic. This occurs when the drainage system is formed incorrectly. The signs usually appear around 4 to 6 years of age. This type of glaucoma is more common to Beagles, Bassets, Cocker Spaniels, and Arctic breeds such as Huskies. Secondary glaucoma is usually caused by another condition. Trauma, tumors, advanced cataracts, and upper-respiratory infections are the most common.
Symptoms may vary from animal to animal, but most people notice cloudiness and swelling in the eye. Other signs can be redness in the eye, dilated pupil, rubbing the face on objects—including you—and squinting. Untreated, this will end in blindness for the pet. Animals can cope with blindness, but this condtion is very painful. When one eye is affected, the other eye usually develops glaucoma within 8 months.
The best treatment is to visit an ophthalmologist to confirm glaucoma. The doctor will do a thorough exam and use things such as a tonometry to measure eye pressure and a gonioscopy to help determine how long before the other eye will be affected.
There are two types of treatment: medical and surgical. Medical treatment is a lifelong commitment to eye ointments and possible oral medications. Surgical treatment may include laser surgery or cryosurgery. The goals for both of these treatments is to reduce IOP, reduce the amount of fluid produced, increase drainage, and provide pain relief. Remember, your pet doesn’t always tell you when he is in pain.