Nearsightedness Index Page About Refractive Surgery R efractive surgery is a term for several procedures designed to treat refractive errors such as nearsightedness, farsightedness and astigmatism. How The Eye Works Clear vision in the normal eye is the result of light rays passing through the cornea, pupil and lens and focusing directly upon the retina.
Nearsightedness occurs when the cornea is too curved or the eye is too long.
This causes light to focus in front of the retina, resulting in blurry distance vision. Farsightedness occurs when the cornea is too flat in relation to the length of the eye. This causes light to focus at a point beyond the retina, resulting in blurry close vision and sometimes blurry distance vision too. Astigmatism occurs when the cornea is shaped like a football, more curved in one direction than the other, and often occurs with nearsightedness and farsightedness. This causes light to focus on more than one point, resulting in blurry or distorted vision.