LVC or Laser Vision Correction is the use of a laser to reshape the cornea allowing light to focus on the retina without the aid of glasses or contacts. The cornea is the transparent tissue in front of the iris. It is shaped like a lens and like the lens of a camera it bends light to create an image.
Patients who are near sighted (myopia) either have a cornea that is too steep or an eye that is a too long and the incoming light travels beyond its focal point creating a blurred image on the retina. Farsighted patients (hyperopia) have the opposite problem. In their case the cornea is too flat or the eye too short and the incoming light hits the retina before it can come into full focus. For patients with astigmatism, the cornea is not spherical having a more elliptical shape. As a result the image is smeared over a distance rather than being focused to a single point.
LVC works by flattening the central cornea in patients with myopia, steepening the central cornea in patients with hyperopia and variably flattening and steepening to make a more spherical cornea in patients with astigmatism.
To accomplish the reshaping of the cornea, the EXCIMER laser (an argon gas laser getting it’s name from EXCited IsoMER) bombards the corneal tissue with high energy photons (light particles) breaking carbon bonds and vaporizing tissue. The extreme precision of Excimer lasers has allowed for the reliable outcomes with low enhancement rates in LVC.