Waring G O, Lynn M J, Gelender H, Laibson P R, Lindstrom R L, Myers W D, Obstbaum S A, Rowsey J J, McDonald M B, Schanzlin D J
Ophthalmology. 1985 Feb;92(2):177-98, 307. doi: 10.1016/s0161-6420(85)34054-x.
The Prospective Evaluation of Radial Keratotomy (PERK) study is a nine-center, self-controlled clinical trial of a standardized technique of radial keratotomy in 435 patients who had physiologic myopia with a preoperative refraction between -2.00 and -8.00 diopters. The surgical technique consisted of eight incisions using a diamond micrometer knife with blade length determined by intraoperative ultrasonic pachymetry and the diameter of central clear zone determined by preoperative refraction. At one year after surgery, myopia was reduced in all eyes; 60% were within +/- 1.00 diopter of emmetropia; 30% were undercorrected and 10% were overcorrected by more than 1.00 diopter (range of refraction, -4.25 to +3.38 D). Uncorrected visual acuity was 20/40 or better in 78% of eyes. The operation was most effective in eyes with a refraction between -2.00 and -4.25 diopters. Thirteen percent of patients lost one or two Snellen lines of best corrected visual acuity. However, all but three eyes could be corrected to 20/20. Ten percent of patients increased astigmatism more than 1.00 diopter. Disabling glare was not detected with a clinical glare tester, but three patients reduced their driving at night because of glare. Between six months and one year, the refraction changed by greater than 0.50 diopters in 19% of eyes.
放射状角膜切开术前瞻性评估（PERK）研究是一项在九个中心开展的自我对照临床试验，针对435例生理性近视患者，术前屈光度在-2.00至-8.00屈光度之间，采用标准化放射状角膜切开术技术。手术技术包括使用钻石微米刀进行八处切口，刀片长度根据术中超声测厚确定，中央透明区直径根据术前屈光度确定。术后一年，所有眼睛的近视度数均降低；60%的眼睛屈光不正度数在正视眼±1.00屈光度范围内；30%的眼睛矫正不足，10%的眼睛矫正过度超过1.00屈光度（屈光范围为-4.25至+3.38 D）。78%的眼睛未矫正视力达到20/40或更好。该手术在屈光度在-2.00至-4.25屈光度之间的眼睛中效果最佳。13%的患者最佳矫正视力下降了一或两行Snellen视力表视力。然而，除三只眼睛外，所有眼睛均可矫正至20/20。10%的患者散光增加超过1.00屈光度。临床眩光测试仪未检测到致盲性眩光，但三名患者因眩光减少了夜间驾驶。在六个月至一年之间，19%的眼睛屈光度变化超过0.50屈光度。
