Options abound for corrective glasses to help see near and far
BY DR. KOMOROFF Universal Uclick
Monday, January 21, 2013
1/21/13 at 4:17 AM
Dear Doctor K: It's finally happened - I need reading glasses! Can you help me sort through the different types of corrective lenses?
Dear Reader: If you're over 40, there's a good chance you are like me. I have both myopia (difficulty seeing distant objects clearly) and presbyopia, which makes reading difficult.
In myopia, objects in the distance do not focus sharply on the retina. Glasses can bend the light entering your eyes from distant objects and focus the light on the retina.
When we look at something close up, as we do when we're reading, little muscles tug on our lenses to change their shape. That change causes the page we're reading to focus sharply on the retina. As we get older, our lenses lose their flexibility; they no longer can focus near objects properly. Glasses can bend light coming off the page so that it focuses better on the retina.
If you have only presbyopia, the simplest answer is to wear reading glasses. Many people need different amounts of correction in each eye and therefore require custom glasses.
If, like me, you have both myopia and presbyopia, one option is two sets of glasses: one for distance vision and one for close vision. Or you can wear bifocals, in which the upper portion of the glass corrects for distance and the lower portion for near vision.
Another option is trifocals, which correct for middle vision in addition to distance and near vision. Trifocals may be a good choice if you spend a lot of time looking at objects at a middle distance, such as a computer screen.
Progressive lenses are another option. They combine several levels of adjustment to correct both distance and close-up vision. (I've put an illustration of different corrective lenses on my website, tulsaworld.com/DrK.)
Contact lenses, like glasses, can correct just for myopia or just for presbyopia. Bifocal, trifocal and progressive contact lenses are also available.
Write Dr. K at www.AskDoctorK.com or c/o Universal Uclick, 1130 Walnut, Kansas City, MO 64106