If the words corneal topography make you think of maps, your instincts are right on. The corneal topography of your eyes is a map of the surface of your corneas: how they curve, whether they're even, and if any irregularities show up.
WHY DO DOCTORS USE CORNEAL TOPOGRAPHY?
Corneal topography is measured with a computerized mapping tool that determines the curvature of the cornea's surface. Because the cornea takes care of about 70 percent of the eye's refraction, a cornea that's rounded evenly is important for healthy vision. Corneal topography helps eye doctors determine when a patient's cornea is misshapen, and it can detect results that other testing methods don't catch.
HOW DOES THE MAPPING WORK?
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The procedure is painless and lasts only for a few seconds per eye. Patients look into a bowl-shaped device that contains illuminated concentric rings. In the center of the device is the camera that captures the surface of the cornea. The concept of reflecting rings in the cornea to measure irregularities dates back to the 1880s; current machines can map thousands of points across the cornea in seconds. The computer then uses both the height and the position of those points to create the map that the eye doctor examines and interprets.
WHAT IS AN ABNORMAL CORNEA?
Corneal topography technology detects corneas that are abnormally curved. That can mean they curve more steeply than normal, are flatter than normal, or are asymmetric in some way. Abnormal corneas may develop over time due to eye injury or disease, which is why it's important to get a corneal topography test every time you go to the eye doctor.
WHY HAVE YOUR CORNEAS MAPPED?
If you wear contact lenses, chances are you've stared into a corneal topography machine. Most eye doctors use corneal topography to help fit contacts correctly. Similarly, if you have LASIK or are looking into LASIK, the eye doctor will use the corneal topography machine to help determine how the LASIK surgery is going to go. In laser eye surgery cases, the corneal topography results combine with other tests to determine the overall surgery path. Corneal topography results can help doctors diagnose many issues, from corneal abrasions to diseases like keratoconus, which happens when the center of the cornea begins to thin and form an outward bulge. In cases of complex problems like keratoconus, corneal topography is just one test eye doctors use to find the disease and figure out how severe it is. Corneal topography maps also monitor the amount of astigmatism that sometimes occurs after corneal transplants or cataract surgery. Getting the corneal topography of your eyes measured is important, which is why you should see your eye doctor regularly even if you don't have poor vision. Plus, the machine doesn't touch your eye, and the picture is over in seconds, so it's a quick and easy test. Eye health is measured by more than just whether or not you can see 20/20 without correction, so make sure you're taking care of your eyes.