Understanding Refractive Errors - Your Vision

Clear vision is the result of light rays passing through the cornea, pupil, and lens and then focusing directly on the retina. Glasses or contacts correct for refractive errors that prevent the eye from focusing properly.

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 a blurry distance image. Myopic Lasik will flatten the curvature.

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, especially as one ages. Hyperopic Lasik will steepen a flat cornea.

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 cause light to focus in more than one point on the retina, resulting in blurry and distorted vision. Lasik is able to correct for astigmatism.