Conventional LASIK involves cutting a flap in the outer layer of the eye's cornea and then re-shaping the tissue underneath with a laser. Wavefront technology is a diagnostic tool that allows doctors to customize the surgery by making a more detailed map of the eye's structure. Some have compared the two approaches to buying a custom-made suit from a tailor rather than off the rack, or of using a map of a specific city to find your way, instead of a map of the entire state.
How does wavefront work? Light from a laser beam is shone into the eye to the retina, and is then reflected back out. A special sensor measures the light that comes out and compares it with the pattern of light that went into it. This produces a three-dimensional map of the eye's visual system. Any difference between what goes in and what comes out usually results from a distortion in the eye. This information is translated into a mathematical formula that the surgeon can use to program corrections into the laser. The laser can then reshape the cornea to correct vision errors.
The usual eye examination can only diagnose the most common types of vision problems. A wavefront diagnosis can detect more serious problems that are not detected by conventional diagnostic methods. These can cause glare, halos or blurry images. The three most common types of vision problems are:
- Myopia: near-sightedness, or trouble seeing things at a distance
- Hyperopia: far-sightedness, or trouble seeing things up close
- Astigmatism: an irregularly shaped cornea in the eye