GLAUCOMA AS IT IS: WHAT IF THERE’S NO DAMAGE YET?
60-70 years ago, when people didn’t live as long, diagnoses of glaucoma were not that common. It’s because glaucoma is a cunning disease. The eyes don’t hurt, and loss of vision doesn’t come for a long time. In case you’ve forgotten, glaucoma is neuropathy of the optic nerve that results in atrophy and fiber loss.
We’re born with 1.5 million fibers and gradually lose them, like most everything else. But if a normal person has lost, let’s say, 10% of fibers over 100 years, those with glaucoma lost a lot more. Those with advanced glaucoma have a completely atrophied optic nerve and are blind.
Risk factors include ethnicity. Heredity is also a factor. People that have close relatives with glaucoma are also at-risk. Since it causes an irreversible loss of fibers and vision, the only thing we can do is slow the process. This requires an early diagnosis, though.
The sooner treatment begins the better, whether that’s eyedrops, painless and effective laser treatment, or surgery. Sticking your head in the sand and reasoning that “Well, if you go to the doctor, they’ll find something wrong with you” is dangerous.
In many people that come to us, we find nothing. We ask them to come back in a few years. The proper attitude is to be vigilant. If your optometrist, or better yet ophthalmologist, notices any changes in the optic nerve, you need to undergo a battery of tests. This is the same with increased intraocular pressure or hereditary risk factors.
It’s a process and you need to go with the flow. They take images of the optic nerve, along with visual field tests using laser interferometry. It measures the thickness of the optic nerve and nerve fibers. They check this year-to-year against a normative database.
GLAUCOMA AND WAVES?
All of these tests, unfortunately, only measure damage that already exists. Diagnosis proves difficult if there isn’t any yet. A couple of years ago, we had the new Visual Evoked Potential diagnostic system. It was non-invasive and only involved attaching wires similar to a cardiogram.
When light hits the retina, the brain and optic nerve turns this into electrochemical energy. We measure these electrical signals in wave parameters. Previously, however, this was only available in special laboratories, but it is now included in clinical practices. Some ophthalmologists have it.
A person takes 5 minutes to adapt to the darkness and a technician attaches electrodes under the eyelids and back of the head. They then show the patient images that cause certain waves. They summarize it, analyze it, and compare it to the normative database. And it works for more than glaucoma!
(to be continued)