THE COMBINED (GENESIS) TECHNIQUE OF RADIAL KERATOTOMY - A PROSPECTIVE, MULTICENTER STUDY

Purpose: A prospective, multicenter, clinical study to evaluate a stan dardized surgical (Genesis) protocol which includes combined-technique radial incisions in patients seeking reduction of their physiologic m yopia. The combined incisions were designed to incorporate the safety of the centrifugal incision technique with the efficacy of the centrip etal incision technique. Methods: A total of 375 eyes undergoing radia l keratotomy procedures performed in six different clinical centers we re analyzed. All procedures were performed in accordance with the Gene sis nomograms. The Genesis protocol called for using preoperative scre ening pachymetry to guide central clear zone size selection, incising the thinnest corneal quadrant first, suturing corneal perforations, an d discouraged more than one enhancement procedure, when indicated. Glo be fixation technique served as a study variable. Results: Mean follow -up was 6.2 months (range, 1.5-12 months). Mean residual cycloplegic r efraction was -0.48 +/- 0.61 diopters(D)(range, -2.50 to +1.50 D); 92% of eyes were within 1 D of the planned goal of -0.50 D and 85% were w ithin 1 D of emmetropia; 14% were myopic; and 1% was hyperopic by more than 1 D. Uncorrected visual acuity was 20/40 or better in 95% of eye s; the remaining 5% retaining myopic refractive errors. A single proce dure was performed in 73% of eyes, and 99% received less than two enha ncements. Of eyes with no enhancements, 97% had uncorrected visual acu ity of 20/40 or better. One study eye (0.3%) had a two-line loss of sp ectacle visual acuity. There were no invasions of the central clear zo ne. Globe fixation was a significant predictor for enhancement inciden ce (P < 0.001) but not for perforation incidence (P = 0.06). Incision sequence was predictive for perforation incidence (P < 0.0002), Conclu sion: The combined-technique of radial keratotomy, coupled with the Ge nesis surgical protocol, affords centrifugal incision safety with cent ripetal incision efficacy. The Genesis nomograms, with a built in refr active outcome goal of -0.50 D provide an acceptable degree of accurac y and predictability while guarding against hyperopic overcorrection.