How Laser Eye Surgery Works
The retina, a light sensitive layer at the back of the eye, can receive distorted images it relays to the brain if the cornea, the clear front surface of the eye, is misshapen. A device called an Excimer laser can be used to direct a beam of ultraviolet light on the cornea to vaporize tissue and restore its correct refractive shape. Depending on the type and extent of vision problems, there are currently four types of laser surgery available.

Common Laser Procedures
The two types of laser surgery performed most commonly are PRK (Photo-Refractive Keractectomy), first introduced in the early nineties, and LASIK (Laser Assisted in situ Keratomileusis), introduced in the mid-nineties. There are also two more recent procedures called LASEK (Laser Epithelial Keratomileusis) and Epi-LASIK. Your doctor will recommend which methods best suits you.

PRK
In this procedure, the surgeon removes the outer layer of the cornea with a surgical instrument. The laser beam, guided by a computer, then vaporizes tiny amounts of tissue under the surface of the cornea. The procedure removes just enough tissue to reshape the cornea correctly. The initial healing process is complete within a week.

LASIK
This surgery is more complicated. The surgeon first cuts a flap in the cornea with either a blade or laser. The flap is lifted and the computer-guided laser burns calculated amounts of tissue from the inside layers of the cornea. The flap is laid back in place and the eye heals within a few days.

LASEK
This is a variation of PRK and LASIK and is used for minor vision corrections. The surgeon cuts the outer layer of the cornea with a fine blade and lifts it in a single layer. The laser beam is then directed at the underlying tissue. When the laser procedure is finished, the outer layer of the cornea is put back in place. The healing process takes about two weeks.

Epi-LASIK
This is a modified LASEK procedure in which the outer layer of the cornea is removed with a different mechanical device rather than a sharp blade. Like Lasek, a section of the outer layer of the cornea is completely removed and put back in place to heal. It also takes about two weeks to heal completely.

The Benefits
In most cases, laser eye surgery is successful, eliminating the need for prescription eyeglass or contacts. However, in some cases, vision is not perfect but vastly improved. In these situations, eyeglasses may be necessary in certain contexts, such as reading, driving at night or when long distance vision is compromised. Like all medical procedures, laser eye surgery poses some risks.

The Risks of Laser Eye Surgery
With PRK, the risks include moderate to severe pain in the first few days of recovery, hazy vision during the healing process and, in some cases, regression to previous refractive error within about six months. If this happens, the patient may need a second operation or “enhancement” if they do not want to return to wearing glasses or contacts.

With LASIK, there is less post-operative pain. However, since this procedure involves cutting into the cornea, there is a greater risk of dry eyes or poor quality of night vision due to halos and glare. Rarely some patients develop corneal ectasia -- a weakening and bulging of the cornea. This may need to be treated with a corneal transplant or implant.

The more recent LASEK surgery reduces the risk of some of the complications associated with cutting a flap in the cornea, such as weakening of the eye and dry eyes.

The risks of laser eye surgery go up significantly for people with certain conditions or lifestyles. When weighing the risks, you should consult with the surgeon about your medical condition, family medical history, and athletic activity.

Many people over the age of 40 find they need reading glasses after laser eye surgery even when they did not before surgery. Also, it is important to realize that your eyes will continue to change as you grow older, and you may need prescription glasses or contacts again at some point. Finally, because this is a relatively new procedure, the long-term effects of laser eye surgery are still unknown.

Patient surveys have shown that the vast majority of those who elected to have laser eye surgery are happy with their choice. The quick recovery, freedom and flexibility gained, money saved by not having to buy new contacts and glasses, and sharpened vision opens up a new world for those who opt for these procedures.