Refractive surgery is not new. Over the past fifty years, several techniques have emerged as potential "cures" for nearsightedness. Most of the early procedures were unpredictable and were soon abandoned. One technique tried in Japan resulted in blindness for all of the participants. In the early 1970's, a Soviet Union ophthalmologist developed a technique known as radial keratotomy (RK). Improvements in both the technique and the instruments used have made it the most common incisional refractive surgery performed today.

What is Radial Keratotomy (RK Surgery) and how does it work?

The cornea is the clear, most anterior portion of the eyeball. It is the most powerful focusing structure in the eye. Most nearsightedness results from an excessively curved cornea which causes light to focus in front of the retina at the posterior portion of the eye. After the RK incisions are made, the cornea flattens.

How do you make the incisions so the cornea flattens the right amount? By varying the size of the optic zone you can control the amount of flattening the incisions will produce. The longer the incisions, the smaller the optic zone, thus the greater will be the flattening of the cornea. The incisions are made nearly the full thickness of the cornea with a very precise diamond-edged scalpel. The actual thickness, which is typically .5 millimeters, is determined by an instrument called a pachymeter.

One of the advantages of RK surgery is the minimal pain that results from the incisions. This is not true with laser surgery which requires that the outer cells of the cornea be scraped off before the laser beam is applied. Another advantage of RK surgery is the rapid recovery. Patients who have had laser surgery often complain of hazy vision for several months after the procedure.

Laser Surgery

While radial keratotomy has been the most prevalent technique used over the past twenty years, it does have disadvantages. With moderate to higher degrees of myopia, long-term stability seems to be a problem. Laser procedures have virtually eliminated RK as the technique of choice for moderate to high myopia. Lasers are not so dependent on the skill of the surgeon, and since they are computer guided they produce fairly consistent results.

A laser beam is produced when a mixture of gases is brought together in a high-voltage cavity. By using Argon and Fluoride gases, a cool ultraviolet beam of light can be computer guided to vaporize just the right amount of tissue to flatten the cornea. This reduces the nearsightedness.

There are two procedures for reshaping the front surface of the eye, Photorefractive Keratectomy (PRK) and Laser-Assisted Intrastromal Keratomileusis (LASIK). PRK involves first removing the outer layers of the clear cornea and then precisely removing exposed corneal cells as determined by the computer program which has analyzed the particular patient's eye characteristics.

The LASIK procedure involves establishing a corneal flap by cutting across the cornea. The flap is pulled back and the underlying tissue is reshaped by the laser. The flap is then returned to its normal position where it reattaches itself. LASIK is the most effective procedure for prescriptions greater than 6.00 diopters. It has the advantage of much less discomfort because the epithelium is not removed. Also, haze is greatly reduced so both eyes can be done at the same time. This procedure has only been done for five years as compared to PRK's nine years and RK's twenty years. 

So the ultimate question is, should I have a refractive surgery procedure done on myself, and is it safe? From a statistical standpoint, the procedures we have talked about are safe. Your satisfaction with your visual outcome is very dependent on your expectations. If 20/20 unaided acuity is a must, then you would be better off with contact lenses or glasses. If you do not like wearing glasses, and you have found contact lenses intolerable, or you are too impatient to bother with contact lenses, then refractive surgery is for you. 

Who should do your surgery? Probably not the doctor with the biggest ad in the newspaper, or the one who claims he has done his cat and wife (hopefully in that order). I look for a doctor who has solid clinical and research-based experience. A strong staff that not only coordinates care with the surgeon, but also plays an integral role in your education about refractive surgery, is very important. While I make every effort to advise and educate you as well as answer your very important questions at the preoperative examination at my office, I expect the surgeon and his or her staff to reinforce the important issues regarding your specific refractive procedure.

 Questions and Answers about Refractive Surgery