Q. How does a radial keratotomy operation proceed?

A. The patient is given a mild sedative prior to surgery. The eye is prepped normally. Generally the non-dominant eye is selected for the first go-around, leaving the fellow eye to wait a minimum of one week before surgery on it; although this interval could vary. However, under no circumstances are both eyes operated upon on the same day!

During the operation the front surface of the eye is numbed with drops. Some surgeons advocate retro-bulbar anesthesia, however, its use is not warranted and some of these cases have developed acute optic atrophy with total vision loss as a result. Microscopic radial slits are cut into the cornea, without touching the inner eye, to reshape the corneal curvature (Figure). This allows light rays to once again focus on the retinal screen and permit clear vision. The operation is relatively bloodless and painless.

Precise microscopic control must be maintained over the length, depth and arrangement of these micro-incisions in order to achieve proper optical correction. The knife blade used is generally a crystalline blade such as sapphire for best results and more uniform cuts. These micro-incisions allow the central cornea to flatten, thus partially or fully correcting the myopia. Upon completion of the incisions, each one is gently irrigated with BSS. Antibiotic and cycloplegic drops are then applied and the lid speculum removed. A patch is then placed on the eye and removed in approximately 2 hours. During this period of time, the patient must avoid getting the eye patch soiled or wet, but otherwise there are no restrictions placed on the patient. Antibiotic drops are used for l - 2 weeks after the surgical procedure.

By changing the pattern of the radiating incisions and incorporating tangential incisions, astigmatism up to 8 diopters can be corrected. The range of expected correction of spherical myopia is from <1 to 7 diopters, although higher corrections have been reported. Occasionally a second operation is needed to reduce any residual myopia.

Vision is usually good from week one but fluctuation of vision from morning to night can be expected for upwards of 6 months and sometimes longer. Glare at night can also be expected for the same length of time. Some patients have complained up to 3 years, however, glare testing shows no significant glare after 1 year in 99.3% of the cases. Approximately 83% of patients in the expected range achieve 20/40 unaided (or better) vision post-op. Regression of effect over time has not been observed with the newer techniques.

The incidence of severe complications is rare and compares favorably with those associated with the wearing of soft contact lenses or spectacles. While there has been some recent unfavorable publicity about serious complications none can be ascribed to the surgery itself. Out of 380,000+ cases performed in the U.S., only two eyes have been lost as a consequence of the surgery — both from post-operative infection. Other complications such as cataract formation have been due to physician error or the use of steroids. One case of retinal detachment occurred as a result of the use of Phospholine Iodide — a notorious culprit in producing this problem. There have been some reports of continuing corneal flattening leading to over-correction. These studies have defects which throw suspicion upon the results and have not been corroborated by other workers.

Q. How long does the operation take?

A. It usually takes 30 minutes to perform. Only one eye is operated on at a time. The second eye is done approximately a week later. By then, the postoperative reaction is gone and we can better assess the immediate results of the surgery. Such results may influence the way that the surgery is performed on the second eye.

Q. Does radial keratotomy require hospitalization?

A. No, the surgery is performed on an outpatient basis in BEI's specially equipped operating room.

Q. Are there any after-effects from the operation?

A. For the first 24 hours after the surgery, you may experience sensitivity to light, a scratchy sensation and redness in the operated eye. There may also be some pain, but that can be taken care of with medication.

Q. How soon will I be able to see after surgery?

A. That varies with each patient. Some see clearly right away. Most others have an immediate improvement with a gradual clearing over a few weeks.

Expected Results

We measure the degree of myopia in terms of a unit called a diopter. Most myopes measure less than five diopters although very high myopes can go above ten diopters. Although up to ten diopters of correction have been achieved through the procedure of radial keratotomy, the normal maximum amount of correction following this procedure is approximately seven diopters. Therefore, the average myope can expect the possibility of a full correction of their myopic condition.

Even a very high myope can get a definite visual improvement through a partial correction following the procedure. In fact, one of the happiest patients I have seen was a gentleman who went from nine diopters of myopia to three diopters. Even though he was still myopic, he thought the improvement was very significant and was quite pleased with the results.

Q. So not everybody gets out of glasses?

A. That's correct. A large percentage do; the rest have to wear glasses at least part of the day. In all but a very tiny percentage the myopia is reduced in severity and the required glasses are much thinner.

• Surgical Technique
• Side Effects
• Complications