The human eye works by sensing light reflected off objects around it. If you are in an area with no light, you can not see objects around you. This is pretty obvious, but they way your eye deals with the light can be a large factor in why you are having trouble seeing. In order to see things clearly, your eye must focus light inside of it just right.

Normal Eye

In a normal eye, light passes through the lens of your eye and has a focal point on the Retina. The retina is a thin layer of tissue on the inside of your eyeball. This type of eye has an ideal amount of curvature in the cornea in relation to the eye's length.

Near-Sighted Eye

In a near-sighted eye, the focal point comes up short and causes you to see things better up close. This can be caused from your cornea being overly curved and/or your eyeball is too long. Because the focal point of light in a near-sighted eye is too short, the light rays are able to spread appart and cause a blurry image.

Far-Sighted Eye

As you would have guessed, a far-sighted eye has the exact opposite problem that a near-sighted eye has. In a far-sighted eye, the focal point is behind the retina and causes an up close object to be blurry. A common misconception about being far-sighted is that you are not a candidate for Lasik. This is not true, and being far-sighted does not automatically disqualify you from being a candidate for Lasik.

What is Astigmatism?

Astigmatism is a condition where the cornea is an irregular shape (non-spherical). This causes light to have multiple focal points, causing blurry vision. It is possible to be near-sighted or far-sighted and still have astigmatism. Astigmatism shares the same myth about Lasik candidacy that far-sighted eyes have. If you have astigmatism, this does not automatically disqualify you from being a Lasik candidate.