by Richard P. Holm
The first indication of my having glaucoma came when I was at the eye doctor for a regular checkup. It was discovered by machine-testing that I had lost peripheral vision in my left eye. Loss of peripheral vision is a sign that glaucoma might be occurring, and indeed, when they measured the pressure within my eyes, it was increased on the left. Before that, I had no idea something was wrong.
An estimated three million people in the U.S. have glaucoma; half of which have no idea something is wrong, and 120,000 become blind as a result. Glaucoma is the second leading cause of blindness in the world, especially for those coming from African origins. Treatment is available once the condition is discovered, so the best preventive move is to get routine glaucoma testing.
Glaucoma causes peripheral vision loss and preserves central vision until late in the disease. Central vision is that concentrated view we have of the object at which we are staring. It is the eye-of-the-needle into which we are trying to put the thread; the subtle smile of the mysterious woman about which we are painting; the target at which we are aiming our arrow. Say it again, early on, central vision is preserved in glaucoma.
Just because our central vision is retained until late-stage glaucoma, that doesn’t mean it isn’t causing problems. Peripheral vision is important, allowing us to see the shooting star that flashes suddenly from the eastern horizon while we’re staring at the big dipper; to see the boy that might jet out from behind a car in pursuit of his ball while we drive down the road; to see the guy across the room who has captured our attention, secretly watching him without letting him know.
For comparison, macular degeneration causes the opposite kind of vision loss. More specifically, it results in a loss of central vision while preserving peripheral vision. Both conditions affect the retina, the blanket of nerves covering the back side of the eye, which, like a camera, captures the image of an autumn moon rising above a South Dakota lake, a wind-wave of grass moving on a prairie hill, or the surprised face of discovery on a visiting grandchild.
Take home message: people don’t realize there is peripheral vision loss resulting from glaucoma until the damage has been done. Get in to have routine eye testing. You may have no idea something is wrong.