The Long Term Complications Of Radial Keratotomy

Radial Keratotomy (RK) has been referred to by some as the “Grand Father” of Refractive Surgery. It involved making radial incisions in the cornea some times as deep as 80% of the total corneal thickness in an attempt to flatten the tissue. Astigmatism was treated with specific incisions located in strategic parts of the cornea. The astigmatic incisions were done first, since they created more nearsightedness and when they healed, the radial ones were performed. The optical zone around the pupil varied depending on the degree of nearsightedness that needed to be corrected.

Having seen many thousands of patients that underwent this procedure, I can say with confidence that most complained of glare and the vast majority regressed and required eye glasses not long after the surgery. That period varied from several months to many years. The “father of RK” was Dr. Fyedorov who did his research, and refined his technique on thousands of “very willing” citizens of the Soviet Union. During that time in the 70’s and 80’s his reported results were outstanding. To date it is very hard to find any negative results or complaints from his work. Evidently the Soviet Union may have had a hand in his clinical data reported for public consumption.

RK was brought to the United States by 5 American eye surgeons, two of the most well known being Dr Norman Stahl and Dr Jerry Zelman. They both travelled to Moscow to study with Dr Fyedorov, and I even had the pleasure of being in the office with Dr Stahl when Dr Fyedorov visited him in his Garden City, Long Island office. Dr Stahl was an outstanding doctor and surgeon, and personally performed many thousands of RK procedures. In the short term, most patients were happy with the results. However, where are these patients today? How do they see and what do their corneas look like so many years after having surgery?

I have had the pleasure of examining a number of these same patients years after their procedure. Most, if not all of these folks that I examine require an eyeglass prescription. Most are farsighted, and have a significant degree of astigmatism as well. Their prescriptions are generally unusual, and have acquired unconventional astigmatism. Another very common finding is the presence of a brown semicircular ring in the inferior half of the cornea. The inner most layer of the cornea is a single layer thick, and when RK was performed that layer was stretched thin as required to cover a larger area. Its function is to pump fluid out of the cornea, and keep it at the proper hydration level. However, as this thin layer was stretched out its function was negatively affected. As a result, it left the heaviest materials behind; Iron. Therefore, this brown deposit is iron left in the cornea by a weakened endothelium layer. It does not appear to have any visual effect, or create any physiological determent, but is a constant. What the future holds for these patients is still a question mark.

The big question is why all these patients are farsighted, and what can be done about it. The answer to the first question is still a mystery. It is possible that they were deliberately over corrected to compensate for the regression or more likely, the corneas were so weakened by the RK that they became flatter over time, and warped causing the astigmatism. Unfortunately, both Drs Stahl and Zelman have passed away and are not available for consultation regarding this matter. A weakened cornea is free to change with out any guidance, since both internal and exte
al pressures can reshape it. The one constant is that they all need some refractive help. In fai
ess to all the RK surgeons, today’s technology was not available to them. There were no topographers, no Orbscans, and many other measuring instruments that we routinely use today. In addition, surgical calculations were made on a regular refraction. The FDA and all the surgeons did not require cycloplegic refractions which eliminate any spasms of the focusing system abnormalities from impacting the presurgical calculations.

Many of these patients are having PRK as a way of correcting their vision and improving their distorted vision. At least today’s technology has corrected the errors of the past. One must question if 20 years from now we will be having the issues about LASIK or PRK.