Glaucoma & Pseudoexfoliation


Glaucoma  is a disease of the eyes where there is an increased pressure  (intraocular pressure) inside the eye. The increased pressure damages  the optic nerve, which connects the eye to the brain. The damage to the  optic nerve and adjacent retina causes permanent loss of vision, first  peripherally and eventually the central vision is lost.

There are two main types of glaucoma. The rare type is called narrow angle or acute angle closure glaucoma. By  far, the most common type of glaucoma is called open angle glaucoma.  Open angle glaucoma is often called a silent thief of vision, because  most people have no signs or symptoms of this disease till they lose a  lot of vision. Approximately 2.2 million Americans have open angle  glaucoma, and about 120,000 are blind from it. Pseudoexfoliation  glaucoma is the most common type of open angle glaucoma, accounting for  over 10% of cases of open angle glaucoma. That means there are over  220,000 people with pseudoexfoliation glaucoma in the USA.

Pseudoexfoliation  glaucoma or elevated intraocular pressure is caused by the pseudoexfoliation flakes clogging the trabecular meshwork of the eye,  and preventing fluid inside the eye from draining out properly. Not all  eyes with pseudoexfoliation need to be treated, but if the intraocular  pressure is elevated significantly, pseudoexfoliation glaucoma tends to  be the most difficult glaucoma to treat, because it often causes very  high pressures, which respond poorly to the standard glaucoma  medications or eye drops. Therefore, pseudoexfoliation glaucoma must be  monitored carefully and frequently to prevent permanent loss of vision.  Some cases of pseudoexfoliation glaucoma are misdiagnosed as standard  open angle glaucoma because the eye doctor does not notice the pseudoexfoliation flakes on the surface of the pupil and the lens. In  order to diagnose pseudoexfoliation glaucoma, the surface of the lens  has to be examined with a slit lamp AFTER dilation of the pupil with eye  drops, since the pseudoexfoliation flakes are sometimes very tiny,  subtle and impossible to see without pupil dilation.

Most  cases of pseudoexfoliation glaucoma are treated with eye drops. There  are a variety of categories of drops that can be used, but the treatment  must be carefully customized for each patient since every eye responds  differently and variably to the glaucoma eye drops. Prostaglandin eye  drops (Xalatan, Latanoprost, Travatan-Z, Lumigan, Rescula) are the most common initial drops used to treat the high intraocular pressure in  pseudoexfoliation glaucoma. These drops don't cure the condition, but  they do lower the pressure in the eye and prevent damage to the optic  nerve and loss of vision. If prostaglandin drops don't work well enough,  patients are often treated with additional drops such as  alpha-adrenergic agonists (Alphagan, Brimonidine, Iopidine),  beta-blocker drops (Timoptic, Betoptic, Timolol), carbonic anhydrase  inhibitors (Azopt, Dorzolamide, Trusopt), and rarely cholinergic  agonists (Pilocarpine). Each of these drops has its own safety and side  effect profiles, and various pros and cons. Every eye responds  differently to each drop. Some of the drops can also cause systemic side  effects such as effects on the heart rate, blood pressure, mood, sleep cycle, and other body functions. In more severe cases oral carbonic  anhydrase medications (Diamox, Neptazane, Acetazolamide) are used to  lower the intraocular pressure. These medications can have significant  risks and side effects as well, but may be necessary to prevent vision  loss.

If  the various eye drops and/or pills do not adequately lower the  intraocular pressure in cases of pseudoexfoliation glaucoma, then the  eye is often treated with a laser procedure called argon laser  trabeculoplasty, or selective laser trabeculoplasty. This relatively  safe procedure opens up the pseudoexfoliation flake-clogged trabecular  meshwork and lowers the intraocular pressure in most cases. The  procedure may need to be repeated several times, but in severe or  resistant cases of pseudoexfoliation, the laser procedure benefit is sometimes short lasting.

If eye drop and laser treatments have not sufficiently lowered the  intraocular pressure to a safe level, then eyes with pseudoexfoliation  glaucoma require glaucoma filtering surgery (trabeculectomy, shunt  procedures) to lower the intraocular pressure. These surgeries are a last resort since they carry significant additional risks, but often are  effective.

Patients  with pseudoexfoliation glaucoma need to be carefully monitored by ophthalmologists to make sure that their intraocular pressures are  sustained at a safe level. There is no safe pressure level that is good  for every eye. Some eyes tolerate relatively high intraocular pressures  without loss of vision, and other eyes lose vision with relatively low  intraocular pressure levels. To determine if the intraocular pressure  level is “safe” for each specific eye, ophthalmologists will monitor the  health of the retina and optic nerve using sophisticated scanning  equipment known as OCT and HRT. Additionally, ophthalmologists carefully  monitor the eye's peripheral vision by performing a Visual Field test  from time to time – Humphrey Visual Field testing is considered to be  the benchmark, standard test. Additionally the eye's corneal thickness  must be measured, since eyes that have thin corneas are more prone to  damage from elevated intraocular pressure, especially if the eye has pseudoexfoliation.

Frequent  and careful monitoring of these multiple parameters or tests, and  treatment with the best eye drop, pill, laser or surgery combination is  critical to prevent permanent loss of vision from pseudoexfoliation.  Ophthalmologists who are experienced with the treatment of pseudoexfoliation glaucoma are very familiar with the various diagnostic  and treatment modalities and can explain it to their patients who have  this condition.