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Ocular Surgery News By Luc Haverbeke, MD Special to Ocular Surgery News A patient made an explicit request for bilateral excimer laser photorefractive keratectomy (PRK) for moderate myopia (OD - 3D sphere, 20/20; OS -2.00 -1.00x135, 20/20). Because he had mild astigmatism in his left eye, I persuaded him to have PRK only in the right eye and radial keratotomy in the left eye. The patient underwent the RK procedure on March 10, 1992. He received four centripetal (out to in, the Fyodorov technique) incisions at a 3.75-mm optical zone with a Fyodorov knife set at 105% of the central pachymetry reading. On March 14, the patient underwent PRK on the right eye with an optical of 5mm. The patient's postoperative course is documented on the accompanying corneal topographic images. (not included in this web page) The hourglass configuration of the radials resulted in a slightly asymmetric flattening of the cornea, which effectively neutralized the astigmatism. The patient had 20/15 uncorrected visual acuity in the left eye one week after surgery, which has remained stable through three months. The eye was never treated with steroids during the entire postop course and at the three month postop visit the patient rated his satisfaction as nine on a scale of one to ten with ten being the most satisfied. PRK resulted in a substantial overcorrection at one week postop. The patient went from a preop refraction of -3D sphere to +2.5 +1.5 x 70 at one week postop, and his uncorrected vision was 20/200. The serial images show that the overcorrection regressed, and by three months postop the patient's uncorrected vision is 20/15, but he remains dissatisfied with the result in this eye (six on a scale of ten), perhaps because of the instability of the correction and because he feels the vision is "hazy" when compared to the other eye. He has been using steroids since the procedure and I will have him continue to do so until the eye stabilizes. This case is typical of my experience with PRK. Eyes heal slowly and unpredictably and I feel they need long-term steroid treatment and frequent monitoring. I strongly encourage my patients with -1 D to - 6 D of myopia to opt for RK. |