Waring G O, Lynn M J, McDonnell P J
Prospective Evaluation of Radial Keratotomy Coordinating Centers, Emory University, Atlanta, Ga.
Arch Ophthalmol. 1994 Oct;112(10):1298-308. doi: 10.1001/archopht.1994.01090220048022.
To determine the long-term effects and stability of refraction following a standardized technique of radial keratotomy for myopia in the nine-center Prospective Evaluation of Radial Keratotomy (PERK) Study 10 years after surgery.
Radial keratotomy using eight centripetal incisions was performed to reduce myopia of -2.00 to -8.75 diopters in 1982 and 1983. A mean of 10 years later, patients underwent a standardized ophthalmic examination similar to previous study examinations.
Of 427 patients (793 eyes that underwent radial keratotomy), 374 patients (88%) (693 eyes) returned for the 10-year examination. Of 675 eyes with refractive data, 38% had a refractive error within 0.50 D and 60% within 1.00 D. For 310 first-operated eyes, the mean refractive error was -0.36 D at 6 months and changed in a hyperopic direction to + 0.51 D at 10 years. The average rate of change was +0.21 D/y between 6 months and 2 years and +0.06 D/y between 2 and 10 years. Between 6 months and 10 years, the refractive error of 43% of eyes changed in the hyperopic direction by 1.00 D or more. The hyperopic shift was statistically associated with the diameter of the clear zone. Uncorrected visual acuity was 20/20 or better in 53% of 681 eyes and 20/40 or better in 85%. Loss of spectacle-corrected visual acuity of 2 lines or more on a Snellen chart occurred in 3% of all 793 eyes that underwent surgery. Among 310 patients with bilateral radial keratotomy, 70% reported not wearing spectacles or contact lenses for distance vision at 10 years.
The PERK technique of radial keratotomy eliminated distance optical correction in 70% of patients, with a reasonable level of safety. A shift of the refractive error in the hyperopic direction continued during the entire 10 years after surgery.
在九中心前瞻性放射状角膜切开术评估（PERK）研究中，确定近视患者接受标准化放射状角膜切开术后10年的长期屈光效果及稳定性。
1982年和1983年，采用八个向心切口进行放射状角膜切开术，以降低-2.00至-8.75屈光度的近视。平均10年后，患者接受了与先前研究检查类似的标准化眼科检查。
427例患者（793只接受放射状角膜切开术的眼睛）中，374例患者（88%）（693只眼睛）返回接受10年检查。在有屈光数据的675只眼睛中，38%的屈光不正度数在0.50 D以内，60%在1.00 D以内。对于310只首次手术的眼睛，术后6个月平均屈光不正度数为-0.36 D，10年时向远视方向转变为+0.51 D。6个月至2年期间平均变化率为+0.21 D/年，2至10年期间为+0.06 D/年。6个月至10年期间，43%的眼睛屈光不正度数向远视方向改变了1.00 D或更多。远视漂移与透明区直径在统计学上相关。681只眼睛中，53%的未矫正视力为20/20或更好，85%为20/40或更好。在所有793只接受手术的眼睛中，3%的眼睛在斯内伦视力表上的眼镜矫正视力下降了2行或更多。在310例双侧放射状角膜切开术患者中，70%报告在10年时无需佩戴眼镜或隐形眼镜进行远距离视力矫正。
PERK放射状角膜切开术技术使70%的患者无需进行远距离光学矫正，且安全性合理。术后10年期间，屈光不正度数持续向远视方向转变。
