The different magnification of the front and rear of cheap eyeglasses near me naturally affects the visual effect and comfort of wearing. After optometry, a trial wearing is usually required. Although there is no discomfort during the trial wearing, the resulting lens is uncomfortable.

There are many choices and combinations of inserts when trying on. Many contact lens wearers know that when the prescription exceeds a certain degree, there is a conversion between the prescription of frame glasses and contact lenses. The reason for the conversion is due to the distance between the lens and the eye of frame cheap eyeglasses near me(the distance from the back surface of the lens to the vertex of the cornea).

Different lens combinations may have completely different actual effects. There are many methods to measure the refractive power of a lens, such as posterior vertex refractive power, as well as equivalent refractive power, and effective refractive power.

Effective refractive power refers to the ability of a lens to focus parallel light onto a specific plane, that is, when the same lens moves from one position in front of the eye to another, the actual refractive power of the cheap eyeglasses near me lens will change.

The higher the degree, the greater the difference in distance between the fitting frame and the finished mirror, and the higher the amount of myopia overcorrection. The clarity of the finished mirror is not as high as when it was tried on. When far-sighted, the situation is opposite to near-sighted.

When using a comprehensive optometry instrument for optometry, it can be found that some patients with high myopia sometimes have higher degrees than when trying on the test stand. In addition to close-range perception and instrument adjustment, the distance between the built-in lens groups in the comprehensive optometry instrument is relatively larger, resulting in higher degrees of refraction.