Human Vision and the Eye Essay

571 Words 3 Pages
ABOUT THE EYE

Human eyes receive and form images from outside, also automatically changes in light and seeing things close up and at a distance. Therefore, we can see most of things from outside world. But without light, we can't see anything. Light travels though space and the sun gives off light rays then enter the eyes they are bent or refracted and these light rays create images or picture of all the objects around you, that's why we can see things very clearly. How light enter the eye, first light enters the eye though pupil which control different amounts of light into our eye. Then crystalline lens helps us see clearly, when we look at near objects crystalline lens will grows thicker and when we look at far objects then it will
…show more content…
Therefore, to help nearsighted person to see clear they should wear glasses or contact lenses. The shape of lens help human eye changes the direction of the incoming light rays so the refractions in the eye have a clear image on the retina. So the shape of the lens is important because different kinds of lenses fix different kinds of problem.

Concave lenses are helping nearsighted people to correct their vision. They are thicker on the edges than in the middle.

FARSIGHTED EYE GLASSES

If the eye under converges and light rays focus behind the retina, this is called farsighted person. A farsighted person can see distant objects very clear, but nearby objects such as words in a book is very fuzzy. Convex lenses are helping farsighted people to correct their vision. They are thicker in the middle than at the edges. The following are the diagram to show you how the convex lenses work.

Another vision problem is - Presbyopia a vision problem created by the stiffening of the crystalline lens. People with presbyopia have poor near vision. This happen usually after people after 45.

Multiple Lens On One Glasses

One glasses with three different kinds of lens that you can see objects from farsight, middle place, and nearsight. This kind of glasses is very useful for people who have different kinds of problem on their eye.

MATH QUESTION

1. How far the focal length of the cornea lens system of the eye must change, when the
Open Document