Types of Glaucoma:

There are two main types of glaucoma, primary and secondary. In primary glaucoma, the cause of the increase in pressure is due to a problem in the drainage angle. It is frequently an inherited problem. Beagles, Basset Hounds, and Cocker Spaniels are prone to this type of glaucoma. In secondary glaucoma the pressure is too high because something else is wrong in the eye, such as a lens luxation, bleeding, inflammation, or tumour.

(photo courtesy aec.com)

Aqueous humor made in the ciliary body flows through the pupil into the anterior chamber. Aqueous then drains into the bloodstream through the iridocorneal angle.

Signs:

Bloodshot (red) eye, painful eye, lids may be held shut, tearing, eye may appear cloudy or blue, sudden blindness, depression, appetite loss, enlargement of the eye.

Treatment:

The treatment chosen (i.e. surgery and/or medical therapy) will be influenced by what the goal of therapy is: to stop pain in a blind eye or to preserve vision. Medical treatment consists of a number of different drugs used in combination. Some are given by mouth and effect the whole body, while others are put directly into the eye and have a local effect. The drugs that work when the problem is first diagnosed may not work forever. Therefore, the intraocular pressure needs to be monitored on a regular basis so that the medication regimen can be altered to fit the needs of the patient. Unfortunately glaucoma cannot be cured, only controlled. When medical treatment fails, surgical therapy can help prolong vision.

Medical Therapy:

The following drugs are frequently used:

Carbonic anhydrase inhibitors: Oral and topical formulations reduce the amount of fluid produced inside the eye.

Miotics (Parasympathomimetics): Used on the eye, it helps to increase the outflow of fluid from the eye. It may cause a temporary redness, burning or stinging in the eye.

Beta adrenergic blockers: Used on the eye, to reduce the amount of fluid produced inside the eye.

*By using very small amounts of several of the drugs, the risks of side effects can be reduced.

*Please keep these drugs out of the reach of children.

Surgical Treatment:

In some cases, there are surgical procedures that may provide permanent, or at least long-term control. One of these procedures uses a laser to destroy the part of the eye that produces fluid and thereby reduces the pressure. Another surgery inserts a tube into the eye that shunts the fluid under the conjunctiva (pink tissue) deep in the eye socket. Neither surgery is 100% successful and multiple surgeries over several years may be required to preserve vision.

Blind, painful eyes can be removed to eliminate discomfort for your pet and to avoid the need for medicines that are expensive and affect the whole body. This surgery is called enucleation and the eyelids are permanently sewn shut. Blind painful eyes may also have an intraocular prosthesis placed. With this surgery the contents inside the eye are removed and a sterile silicone prosthesis is placed. The eye is preserved but no longer has the pain from high pressure. Afterwards, the eye looks fairly normal, but remains blind.