Wavefront is used in two separate ophthalmic events. The first is a Wavefront evaluation and diagnosis of the patient’s existing corneal aberrations. The second uses what is learned from the diagnosis to create a Wavefront-guided ablation scheme for the actual LASIK surgery itself.
During a Wavefront diagnosis, light is sent into the eye in a specific pattern, and then measured after it has passed through the visual system. The difference between what goes in and what is measured is considered an aberration. It may help to visualize a square grid going in and a wavy grid coming out: the waves represent aberrations.
A standard eye exam evaluates refraction and low order aberrations (LOA). These are commonly called sphere (myopia, nearsighted, shortsighted or hyperopia, farsighted, longsighted) and cylinder (astigmatism) aberrations. Only a Wavefront diagnosis can measure high order aberrations (HOA), which exist beyond simple sphere and cylinder errors.
Wavefront technology can diagnose and measure aberrations no other system can even see. It is important to understand that without a Wavefront diagnosis, it is impossible for a doctor to accurately determine if Wavefront-guided ablation is necessary for a good LASIK outcome. Similarly, without a Wavefront diagnosis it is impossible for a doctor to accurately determine if a Wavefront ablation is not necessary. In other words, virtually every person considering LASIK should have a Wavefront diagnostic evaluation.
In the case of Wavefront-guided LASIK, the surgical procedure is like standard LASIK, in which a small flap is opened on the cornea and the surgeon uses the Excimer laser — in this case programmed with the data from the detailed Wavefront diagnosis — to ablate precise amounts of the cornea to correct for the patient’s unique aberrations.
The entire procedure is painless, taking no more than 5 — 15 minutes, after which the corneal flap is replaced and the patient returns to normal activity in almost all cases within a day.