Glasses correct vision by taking into consideration the curvature of the eye, the thickness of the eye, and the index of refraction. The glass is cut accordingly to correct each of these.
More Info: Glasses play a big part in helping many people to see clearly. If you have vision that is something other than perfect, you will probably require corrective lenses. You can benefit from glasses if you are near-sighted and have difficulty in seeing objects far away or if you are far-sighted and have problems seeing things close up. Glasses can work for both forms of vision loss. If you are like most people, you may wonder how glasses correct your vision.
Curvature of the Eye
The first thing that happens when you want to correct your vision with glasses is that an eye doctor will take a look at your eyes and evaluate the thickness, curvature, and index of refraction. These details can help the doctor to determine what your vision type is and which lenses will best help to correct it. The curvature of your eye generally determines what type of vision you have. For instance, if you are near-sighted, you will require concave lenses in your glasses. A pair of convex lenses will work to correct far-sightedness.
The thickness of your eyes is also something that must be determined. Both far- and near-sighted people can have a spherical shape to their eyeballs. In people who have astigmatism, the eyeball shape is more of a cylinder, which makes it more difficult for the individual to see things clearly. The doctor will measure the thickness of your eye so that they can determine the best type of lenses for your glasses.
Index of Refraction
Index of refraction is the final aspect of glasses that the eye doctor considers. People who are very near-sighted or who have astigmatism in the past would have no choice but to wear what is referred to as “Coke bottle glasses.” However, thanks to improvements in technology, that is no longer necessary. If you have a higher index of refraction, you can have lenses that are thin but strong enough to correct your vision.
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