Basic Physics Corrective Sight ERT

Want to read the rest of this paper? Join Essayworld today to view this entire essay and over 50,000 other term papers

at our disposal and therefore it has reason to be a valued and highly developed scientific field with such vast research behind it. From birth our eyes are made up of very important lenses. These are used to refract the images of the world through the round opening in the eyes called the pupil. This pupil or the black dot in the middle to others is parried with the circular muscle which surrounds which is called the iris. The iris controls the amount of light entering the eyeball by opening and closing. Just behind the pupil is the crystalline lens which is a small fingernail which is made of layers of a fibrous material that has an index of refraction of roughly 1.40, which forms the shape of a convex lens. But amazingly the lens of the eye is not where all the refraction of incoming light rays takes place.

figure 1

Most of the refraction occurs at the cornea as can be seen in figure1 (above). The cornea is the outer membrane of the eyeball that has an index of ...

Get instant access to over 50,000 essays. Write better papers. Get better grades. Already a member? Login

sight problem, the use of uniformly focused spectacles, this has the same optical focal point or correction over the entire area of the lens. Bifocal the upper part of the lens is generally used for distance vision, while the lower part is used for near vision. Trifocal lenses are similar to bifocals, except that the two focal areas are separated by a third middle area with intermediate focus correction. Progressive or varifocal provide a smooth transition from distance correction to near correction.
The most common type of corrective lenes is ophthalmic or convex-concave, although there are many different profiles and therefore degrees of sight restoration, the most basic of which can ...

Succeed in your coursework without stepping into a library. Get access to a growing library of notes, book reports, and research papers in 2 minutes or less.

CITE THIS PAGE: