Without your retinas, you couldn’t have sight. This layer of tissue half a millimeter thick – less than two-hundredths of an inch – lines the back of the eye. Its millions of light-sensing nerve cells, called rods and cones because of their shapes, convert light into electrical impulses; the optic nerve sends those to the brain, which turns them into an image.
Your retinas can last a lifetime, but they’re fragile. They’re susceptible to eye problems, trauma to the head and eye and other conditions in the body. (You’ll find more information on Horizon Eye Care’s Retina Center page.)
Literally dozens of diseases, some of them extremely rare, can impair vision. Many affect your retina in some way, and some occur more frequently across the general population. The key to keeping retinas healthy is knowing what might threaten them and what warning signs you’re likely to get. Here are half a dozen potential problems to consider:
We all see small spots across our field of sight from time to time. Tiny bits of the jelly that make up our eyes break loose and cast a shadow on the retina. But if they increase in size and frequency, the retina may be beginning to tear, a condition surgery can repair.
If a retinal tear doesn’t get treated, fluid builds up behind it, pushing the retina away from the rest of the eye. Cataract surgery, eye diseases, genetic factors and extreme nearsightedness make this more likely. Blurred vision, flashes of light, loss of peripheral vision or a curtain-like shadow over your visual field will alert you. Surgery can help here, too, but speed matters.
About 10 million people in the United States, most over 55, have this condition, which causes central vision loss. Symptoms include blurred central vision, a warping of straight lines or difficulty focusing on fine details. Drugs injected into the eye or laser surgery can treat this illness.
People with diabetes may notice blurry vision, double vision, dark spots, pressure or pain in at least one eye, trouble with peripheral vision, flashing lights or rings. The disease can be slowed or stopped, but not reversed. Doctors may treat it with injections of drugs or surgery to reduce the leakage of blood or fluid in the eye.
This mostly appears in children, when cancer cells grow in the retina; it can be inherited, though it need not be. The pupil may look cloudy or white, especially in a photograph; an enlargement of the eyeball or redness and infection can be a tip-off, as can crossed eyes. Multiple treatments exist, though your doctor must first determine whether cancer exists elsewhere in the body.
This umbrella term covers genetic conditions that cause retinas to degenerate, mainly in adolescents and young adults. Rods usually suffer first, then cones; night blindness can be an early symptom, as can loss of central vision or color blindness. There’s no cure, but treatments may slow deterioration or even restore some sight.
The key to fighting any of these diseases, of course, is early diagnosis. That’s one of the reasons your doctor dilates your eyes during an exam: He needs to look at the retinas clearly and thoroughly to make sure they’re in good shape.