What are the main parts of the eye? (posted: april 2003)
Summary: Going front to back the main parts of the eye are the cornea, iris (and pupil), lens, vitreous humour, and retina.

What might I need to know about the cornea? (posted: April 2003)
Summary: The cornea is the clear cap of tissue at the front of the eye which provides most of the focusing power of the eye.

What might I need to know about the pupil? (posted: april 2003)
Summary: The pupil is an opening in the iris that controls how much light enters the eye. The size of the pupil in dim light or dark plays a central role in night vision symptoms for many laser surgery patients.

In very simple terms, how does my vision work? (posted: april 2003)
Summary: Light passes through the eye to the back of the eye (retina) where an image is formed and transmitted to the brain via the optic nerve.

What causes near/farsightedness (short/long sight)? (posted: april 2003)
Summary: Elongation or shortening of the eyeball cause light to be focused in front of or behind, rather than on, the retina.

What is astigmatism? (posted: april 2003)
Summary: An assymetrical cornea or, in some cases, lens that causes light to not focus properly on the retina.

What is presbyopia? (posted: april 2003)
Summary: As we age we lose our ability to accommodate, that is, change focus from far to near. This process usually becomes noticeable starting in one's forties. Laser surgery cannot correct both near and distance vision simultaneously when you have presbyopia.

How do glasses or contacts correct these vision defects? (posted: april 2003)
Summary: Corrective lenses are designed to re-focus (bend) light, causing it to focus on the retina instead of in front or behind.

What do the numbers in my prescription mean? (posted: april 2003)
Summary: The first number is the amount of spherical correction (myopia/hyperopia, the second is the amount of cylindrical correction (astigmatism), the third is the axis (location) of the astigmatism, and the fourth (if any) is correction for presbyopia.

How does the 20/20 scale relate to my prescription? (posted: april 2003)
Summary: text

Which eye is OD and which is OS? (posted: april 2003)
Summary: OD = right eye (oculus dextre) and OS = left eye (oculus sinistre).

Why are my glasses and contact lens prescriptions different? (posted: april 2003)
Summary: Glasses are further away from your eyes.