Open Angle Glaucoma
There are two major types of glaucoma. Primary glaucoma is glaucoma without a known specific cause.
Individuals who acquire this disease could not have prevented it from happening. They were simply
destined to develop high pressure with its associated visual loss. About 85 percent of all glaucoma is
of this type.
Open angle glaucoma tends to be prevalent in some families. The more family members who are affected by
glaucoma the greater the chance an individual has of developing glaucoma. On the other hand, primary
open angle glaucoma can be found in a person who has no history of glaucoma. Individuals who have
family members with glaucoma should have regular pressure checks.
Secondary open angle glaucoma is much less frequent and is usually associated with injury to the eye or
caused by some ocular disease. There are many eye diseases that can be associated with secondary open
angle glaucoma. This disease process accounts for about 10 percent of all glaucoma.
Treatment - Open Angle Glaucoma
In all cases of glaucoma treatment is undertaken with the goal of lowering pressure. The objective of
treatment is to lower pressure inside the eye to the normal range between 10 and 20 millimeters of
mercury. Untreated, pressures tend to range from the low 20's to the 30's. However, they can be as
high as 40 millimeters of mercury and in some cases less than 20 millimeters of mercury. In most cases
of glaucoma treatment can help to preserve vision throughout life but at times treatment can fail to
halt the disease progression.
Treatment for glaucoma is targeted at reducing the production of aqueous fluid or by trying to make
the trabecular drainage system function more efficiently. Eye drops are the most common form of
treatment, however there are some oral medications that are used as well. In some cases surgery is
indicated as an alternative to medication or in conjunction with medication. There are over thirty
different medications for treatment providing a wide variety of medical treatment options before
surgery is considered. There are occasional side effects from the drops used to treat glaucoma
such a blurred vision, allergic reactions, shortness of breathe or cardiac arrythmias. Oral medications
can cause numbness and tingling to occur, imbalances in body electrolytes and in some cases
kidney stones and anemia.
Laser Surgery - Open Angle Glaucoma
When medications become intolerable because of side effects or they no longer are effective then laser
surgery can be considered. The way that laser surgery works is by modifying the drainage mechanism of
the eye. The procedure is called a trabeculoplasty.
For many individuals laser surgery can be very effective and in others it may be of little benefit.
However, there is no way to predict before the procedure who will respond and who will not. In many
cases antigluacoma medication will still be required even after laser surgery. Complications include inflammation
and irritation to the eye immediately after the procedure and in some cases the glaucoma can worsen.
Overall the procedure is effective in many individuals and the risks are relatively low.
Filtering Surgery - Open Angle Glaucoma
When medications or laser surgery are not effective in lowering pressure inside the eye then more
invasive surgery is required. A small hole is made in the wall of the eye and the fluid then drains
through the opening and passes under the conjunctiva into a bleb. From there the fluid diffuses away
and the pressure inside the eye is lowered. The procedure is called a trabeculectomy or a filter.
The filtering operation is usually done in a hospital operating room or an outpatient surgery center.
In many cases following a filtering procedure medications are still required for control of pressure.
In some severe cases of glaucoma plastic or silicone shunts are used in conjunction with trabeculectomy
to remove fluid from inside the eye.
Cryoablation Surgery - Open Angle Glaucoma
When other types of surgical procedures become ineffective or because of the nature of the glaucoma,
destruction of the ciliary body, (the tissue that produces the fluid inside the eye), by freezing can
help to control pressure. The procedure works by reducing the total amount of fluid produced inside
the eye. This procedure is usually reserved for cases of end-stage glaucoma and in many cases is not
very effective and has significant complications.
Overall, surgical procedures for glaucoma are effective for control of pressure inside the eye.
However, they are frequently associated with cataract formation and many case still require the
chronic use of antiglaucoma medications.