Patient Seminars | How The Eye Works - Refractive Conditions
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How The Eye Works - Refractive Conditions
How well you see depends, in part, on the shape of your cornea, the eye's clear covering. The cornea focuses light on the retina, which is at the back of the eye. In a normal eye, light is focused correctly onto the retina. When the cornea is not able to focus light on the retina near and farsightedness or astigmatism may result, which leads to blurry vision.
Nearsightedness
In patients with nearsightedness, or Myopia, the
cornea may be too steep. People with nearsightedness can see things close to
them, but have difficulty seeing distant objects. When Laser Vision Correction
is performed on nearsighted patients, the laser removes tissue to flatten the
cornea.
Farsightedness
Patients with farsightedness, or Hyperopia, have
corneas that are too flat. People with farsightedness can see distant objects,
but have a hard time seeing closer objects. To treat this condition, the laser
beam is directed to remove tissue from around the center of the cornea, making
it steeper.
Astigmatism
Astigmatism occurs in people whose corneas are not
spherical or round enough. The normal eye is shaped like a basketball. The
football-shaped or astigmatic cornea makes it difficult for light to focus on
the retina. By changing the pattern of the laser's beam, the tissue is removed
in one direction more than the other.
