There are a number of methods used to surgically correct eyesight nowadays but the most popular choice is Lasik (Laser-Assisted In Situ Keratomileusis). However before the use of modern technology such as laser beams and computers, the original technique was Radial Keratotomy (RK). This involved an Ophthalmic surgeon with a steady hand and a sharp scalpel to make a series of radial cuts in the cornea (the front ‘window’ of the eye), which when healed, would flatten and therefore reshape the cornea. This would theoretically correct short sightedness. The problems occurred mainly due to the fact that the depth of the incisions could cause weakening and progressive flattening of the cornea, after the procedure. This could lead to a number of defects such as progressively blurring vision and starburst patterns around lights.
With the advent of the laser, a more modern method became the norm, called Photorefractive Keratectomy (PRK). This procedure involved the removal of the outer cells of the cornea (epithelium), and then reshaping the corneal surface with an excimer laser, a procedure known as ablation. The epithelial cells were then allowed to grow back normally. Because epithelial cells on the eye regenerate exceptionally quickly the cornea would generally heal completely within a few days. This technique was certainly more successful than RK but did have its own complications. Side effects such as halos round lights and reduced contrast vision were experienced by almost everyone, along with some corneal ‘hazing’. Although serious complications were rare there was always the risk of infection due to the lack of epithelium protection during the healing phase.
Then in 1990 LASIK surgery was developed by a Dr.Lucio Buratto of Italy and Dr. Ioannis Pallikaris of Greece, and it quickly became popular because of fewer complications and was certainly more accurate. The procedure involves cutting a corneal ‘flap’ with a special high precision blade called a microkeratome. This flap was then folded back with the front surface epithelium still intact. The cornea can then be reshaped with the laser and the flap is laid back down. The epithelial cells that were cut with the microkeratome quickly heal and therefore the outer surface is a nice continuous layer that securely holds the flap in place permanently. Although quite uncommon, some complications such as dry eyes, debris under the flap, ghosting or poor vision to name a few, do occur from time to time.
Another technique that is also used nowadays is LASEK or Laser-Assisted Sub-Epithelial Keratectomy (as opposed to LASIK). It can be used if the cornea is too thin to undergo lasik surgery where the microkeratome cuts deeper than the epithelium. In LASEK, the epithelium is peeled off as a layer to allow laser ablation underneath. During the procedure the epithelial layer is preserved with a special chemical solution and then replaced afterwards, so as to allow natural healing. There is generally more pain and slower visual recovery with this technique.
PRK and LASEK allow the epithelial layer to heal entirely and therefore don’t run the risks of a dislocated corneal flap which can occur due to trauma, even after many years with LASIK. However, the latter is still the most commonly used procedure.
There is still a lot of fear amongst many about the long term effects of laser surgery, but it has been around for quite a while now in its different forms. It seems that more and more people are opting for this surgery, due to a number of reasons whether they be for convenience or cosmetic. With the information technology of the internet, increased knowledge on the subject is much more widespread, so barring any major negative eventualities this trend will almost certainly continue.