FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine
GLAUCOMA SURGERY LOOKS LIKE GOOD CHOICE FOR READER'S SISTER
Question: After a routine eye exam, my sister's eye doctor told her that she has glaucoma. He gave her several different types of eye drops, and now wants to do surgery. Her vision seems fine, so does she really need surgery?
Answer: Glaucoma can be a "sneak thief" of eyesight. This is because the most common variety causes a very gradual, painless loss of vision that starts at the edges of your field of view what doctors call your "peripheral vision." Since the center of the visual field remains sharp and clear, the individual with glaucoma doesn't usually realize he or she has a problem until the disease is quite advanced.
You can think of the eye as being akin to a basketball. The shape of the flexible tissues that form the eye are maintained in the "eyeball" shape by the pressure within it, just as a basketball is held in its round shape by internal air pressure. However, the eye is filled with a clear fluid instead of air. This fluid is constantly produced inside the eye and also constantly drained away. The balance between these two processes is what determines the pressure within the eye.
In glaucoma, this within-the-eyeball fluid pressure "intraocular" pressure in doctor lingo is higher than it should be because the fluid isn't being drained away fast enough. This higher pressure makes it increasingly difficult for the heart to pump blood through the small blood vessels within the eye a process that is necessary to nourish the optic nerve. When the intraocular pressure becomes sufficiently high, the optic nerve is damaged, thereby creating an irreversible loss of vision.
Glaucoma is not often diagnosed before age 50. That is, the disease usually takes a course of years often 40 or more before it produces symptoms and can be easily detected. It affects about 5 percent of persons who are older than 65 years and 14 percent of those older than 80. Fortunately, a routine exam by your eye doctor can detect this serious condition before you experience a serious loss of vision. That is why the American Academy of Ophthalmology recommends that everyone between 40 and 64 have an eye examination every two to five years, and those 65 and over have them every one to two years. African-Americans and those who have a family history of glaucoma should begin regular screening for glaucoma at age 20. This is because members of these groups tend to have an earlier onset of the disease and, once it begins, a more rapid progression.
Your sister's glaucoma was obviously detected before she developed serious visual problems. That's great! Medical treatment is usually the first choice for glaucoma, and that is just what your sister has had. There are several types of eye drops that lower intraocular pressure for most people who suffer from glaucoma. Apparently your sister's doctor has had trouble getting her pressure lowered to the desired level. I suspect that's why she's been on several different medications and why her doctor now recommends surgery.
Surgery is done to decrease the resistance to outflow the removal of the intraocular fluid. This procedure may be done using a knife or a "high-tech" laser. Regardless of the specific tools the surgeon uses, the underlying idea is the same: to create an increase in the rate of removal of the intraocular fluid so that the overall pressure within the eye decreases. Fortunately, this surgery is usually successful at bringing the pressure down to normal levels.
Your sister's surgery should enable her to keep her sharp and clear vision. You see, to be of benefit, glaucoma surgery must be done before vision is lost, and the sooner it can be done, the better her chance of maintaining a full field of vision for the rest of her life.
Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.