The Theory and the Classification of Optical Glasses

Eyeglasses have many kinds, and the optical glasses are a special kind of them, for the special eyeglasses lenses.

The theory of optical glasses:

Using lens, prism, contact lenses and
intraocular lens to correct visual acuity, to eliminate eye fatigue,
and to protect or treat eyes. There are many kinds of eyeglasses. If you
want to correct the refractive errors, you should choose optical glasses
and contact glasses. If you want to correct the aphakia, despite the
contact glasses, you can choose to implant the intraocular lens. Apart
of these, there are a variety of protection glasses, beauty glasses,
visual aids for low vision correction and so on. All of them are thin
lens.

The classification of optical glasses:

There are four kinds of optical
glasses. First, lens. It can be divided into two types: ball lens and
column lens. The curved surface of the ball lens is a part of a sphere.
According to the light being aggregated or separate paralleled, there
are convex lens and concave spherical ball lens. Then, the convex
spherical lenses are used to correct hyperopia, presbyopia and aphakis,
while the concave spherical lenses are used to correct myopia. Column
lens also has convex lens and concave lens, for the correction of myopia
and astigmatism or hyperopia respectively.

Second, prism. It is made of two non-parallel and angled lens. It is used to cure some ocular diseases.

Third, contact lenses. It attaches
directly to the surface of the eyes. According to the different using
materials, it has hard and soft contact lenses. The former is made by
glass, and the later is made by hydrophilic. Both of them are used to
correct visual acuity and treat some eye diseases.

The last one is intraocular lens. It is used to implant into the lens capsular bag immediately after the caratact surgery.



Article from:http://www.newsunglasseslive.com/post/237.html