History of Laser Vision Correction
In fact, laser vision correction was first introduced some 24 years ago! It has been estimated that to date, well over 30 million people around the world have undergone laser vision correction surgery. Today, all of us probably have some friends or family members who have already gone for laser vision correction to get rid of their myopia (shortsightedness), astigmatism (san guang), hyperopia (long-sightedness) or presbyopia (lao hua).
HOW IT ALL BEGAN – EARLY PRK
It all started in the early 1990s with the advent of the excimer laser, which was able to remove and reshape microscopic amount of tissue very precisely. It was found that the laser can be applied directly to the cornea surface to sculpt the refractive powers of the eye, much like the way spectacles lenses are made! The very first laser vision correction started with Photorefractive Keratectomy, commonly known as PRK.
When PRK was introduced in the early nineties, it created an immediate stir in the refractive surgery market. It quickly supplanted RK or Radial Keratotomy that was the de facto standard for doing refractive surgery in the eighties.
Radial Keratotomy was the only option if you wanted to correct your myopia or astigmatism in the eighties. Radial cuts are made in the cornea periphery to alter the curvature of the cornea to correct myopia and astigmatism.
However, despite the no-cut, high tech appeal, early PRK did not take off for a number of reasons. The post op recovery process was painful and visual recovery slow. The lasers used then were first generation lasers that were not as advanced and as accurate. Medications used were also not as advanced. This caused eye doctors to seek other alternatives.
How early PRK was done:
1. Numbing eye drops are instilled to the eye
2. A blunt blade is used to scrape the cornea surface cells to expose the underlying cornea tissue
3. The patient is asked to look straight ahead at a blinking light and the excimer laser is used to reshape the curvature of the exposed cornea surface.