When your eye doctor does an exam, the primary thing he/she is trying to determine is whether or not your eye is healthy. The easiest way to tell is to find out how well you see. In other words, is your vision 20/20?
If your vision is 20/20 with your glasses or without any glasses, great. If your vision is not 20/20, “refraction” is the process of putting lenses in front of your eye to see if lenses can bring your vision to 20/20. If you can see 20/20 with refraction, then you just need glasses. If you still cannot see 20/20 with lenses, something is wrong with the eye, and the doctor must find out what. It could be cataracts, glaucoma, diabetes, macular degeneration or other problems with the cornea, lens or retina. Thus refraction shows your doctor right away that there is a medical problem that could threaten your vision.
It is unfortunate that medical insurance does not pay for this valuable test just because it could be used to provide a prescription for glasses. The refraction is extremely important in determining if there’s a serious medical issue. In fact, refraction is just as basic and just as important in diagnosing eye disease as the electrocardiogram is in diagnosing heart disease.