Types of Glaucoma
Pigmentary Glaucoma
Pigmentary dispersion syndrome is a condition in which increased amounts of pigment circulate within the front portion of the eye. It is caused by abnormal anatomy within the eye. The iris falls back against the ligaments that suspend the eye’s lens, rubbing the pigment off the back of the iris. This pigment can block the drainage channel enough to cause an increase in intraocular pressure (IOP). Nearsighted males in their 20s, 30s, and 40s are the most common demographic for this condition.
In cases of pigmentary glaucoma, the IOP often is very high, reaching levels above 40 mm Hg. Pigmentary dispersion leads to damage from glaucoma in 20% to 50% of patients.
Treatment is the same as for other forms of open-angle glaucoma, including medications, laser therapy, or surgery. With adequate treatment, the prognosis for pigmentary glaucoma is good.
Pseudoexfoliation Glaucoma
Pseudoexfoliation glaucoma is a relatively common form of open-angle glaucoma that can cause significantly high eye pressures. This condition is marked by a dust-like protein that is observed inside the eye on the surface of the iris and lens. This material can clog the ocular drainage system, increasing intraocular pressure (IOP). It can occur in one eye or both eyes and is most commonly seen in patients over the age of 70. Pseudoexfoliation glaucoma is found in all ethnic groups, but it is most commonly seen in people of Scandinavian ancestry. It is more common in women than in men.
Treatment is often required for pseudoexfoliation glaucoma, consisting of medication, laser treatment, or surgery. Laser tends to work especially well in this form of glaucoma. Pseudoexfoliation can cause increased risk of complications with cataract surgery. With proper treatment and monitoring, patients with pseudoexfoliation glaucoma tend to do well. Early diagnosis is important.
One interesting fact about pseudoexfoliation is that there are findings elsewhere in the body. The abnormal protein found in the eye can also be found in the skeletal muscles (ones attached to the bones). Patients with pseudoexfoliation have a higher risk of cardiovascular disease, such as heart attacks, so it is important for them to watch the other risk factors for this, such as exercise, diet, obesity, and smoking.
Intraocular Pressure
Elevated intraocular pressure (high pressure within the eye) is the number one risk factor for glaucoma. However, elevated intraocular pressure (IOP) does not always cause glaucoma.
The average eye pressure in adults ranges between 10 mm Hg and 21 mm Hg (“mm Hg” stands for “millimeters of mercury”). There can be significant difference in your IOP throughout the course of a day. This variation is known as “diurnal fluctuation.” We know that most patients with high IOP do not develop glaucoma, and many patients with glaucoma have normal pressures, some of the time. Therefore, intraocular pressure is not a very sensitive tool for diagnosing glaucoma. It is very useful for assessing one’s risk for glaucoma. Also, since the goal in treating glaucoma is to reduce the IOP, it becomes very useful in monitoring treatment for glaucoma.
A variety of methods can be used to check the intraocular pressure, but the most common is applanation tonometry. If you have glaucoma your doctor will set a “target” pressure for you and will work hard to keep the pressure at or below that target to help preserve your vision.
Steroid Glaucoma
Sometimes steroid medications can raise the pressure inside the eye (intra-ocular pressure, or IOP). When that pressure gets high enough to be problematic, it is called “steroid glaucoma.”
Steroid medications are used to treat a variety of medical conditions. They can be administered as eye drops or as injections in or around the eye. These are the most likely to raise IOP. Steroids delivered by pills or nasal spray are less likely to raise IOP (although oral steroids are notorious for causing cataracts). When raised pressure occurs, its onset is usually a few weeks after starting the steroid. It is important for patients who are on steroid drops or who have had injections to have their eye pressure monitored.
If eye pressure does become elevated, sometimes the steroid medicine can be stopped, decreased, or switched to another steroid type, helping to alleviate the problem. It usually takes a couple weeks for the IOP to decrease after stopping the steroid. If the steroid medication was given by injection in or around the eye, the eye pressure may be harder to control.
If medical therapy does not adequately lower IOP, surgery may be required. As with other forms of glaucoma, if IOP can be controlled, patients tend to do well.