Tuunanen T H, Tervo T T
Department of Ophthalmology, University of Helsinki, Finland.
J Refract Surg. 1998 Jul-Aug;14(4):437-46. doi: 10.3928/1081-597X-19980701-10.
To compare the predictability, safety, and stability of photorefractive keratectomy (PRK) in patient groups with low, moderate, and high myopia. The astigmatic component of these corrections was also evaluated.
In 110 patients, 110 consecutive eyes were operated with a VISX 20/20 excimer laser using standard settings and a 6 mm ablation zone for PRK. The eyes were divided into three groups. In low myopia group (N = 52) the intended correction ranged from -1.50 to -6.00 D (mean -4.28 +/- 1.29 D), in the moderate myopia group (N = 34) from -6.10 to -8.00 D (mean -7.05 +/- 0.70 D), and in the high myopia group (N = 24) from -8.10 to -11.50 D (mean -9.40 +/- 1.13 D). Twenty-seven eyes had 0.75 D of preoperative myopic astigmatism. All patients were followed for 12 months and 36% (N = 40) were available for the 24-month follow-up examination.
At 12 months the spherical equivalent manifest refraction was within 0.50 D of intended refraction in 58% (N = 30) of eyes in the low myopia group, 50% (N = 17) in the moderate myopia group, and 29% (N = 7) in the high myopia group. Eighty-seven percent (N = 45) in low, 79% (N = 27) in moderate, and 67% (N = 16) in the high myopia group were within 1.00 D of intended refraction. At 12 months, 88% (N = 46) of the eyes with low myopia, 68% (N = 23) with moderate myopia, and 68% (N = 16) with high myopia achieved uncorrected visual acuity of 20/40 or better, while 6% (N = 16) of the eyes lost and 4% (N = 4) gained two or more lines of Snellen visual acuity. Uncorrected visual acuity of 20/20 or better at 12 months was achieved by 58% (N = 30) of low myopes, 26% (N = 9) of moderate myopes, and 33% (N = 8) of high myopes; 20/25 or better by 71% (N = 37) of low myopes, 39% (N = 13) of moderate myopes, and 42% (N = 10) of high myopes. Overcorrection (> 0.25 D) was detected at 12 months in 31% (N = 16) with low, 38% (N = 13) with moderate, and 67% (N = 16) with high baseline myopia, with statistically significant differences between the low and high myopia groups.
In all groups, the safety of PRK was satisfactory, without major complications; in the high myopia group where corrections exceeded 8.0 D (mean -9.40 +/- 1.13 D) the procedure was only slightly more unpredictable than in low and moderate myopia at 1 year.
比较准分子激光角膜切削术（PRK）在低度、中度和高度近视患者群体中的可预测性、安全性和稳定性。还对这些矫正中的散光成分进行了评估。
110例患者的110只连续眼睛接受了VISX 20/20准分子激光手术，采用标准设置和6mm的PRK消融区。眼睛被分为三组。低度近视组（N = 52）预期矫正范围为-1.50至-6.00D（平均-4.28±1.29D），中度近视组（N = 34）为-6.10至-8.00D（平均-7.05±0.70D），高度近视组（N = 24）为-8.10至-11.50D（平均-9.40±1.13D）。27只眼睛术前有0.75D的近视散光。所有患者随访12个月，36%（N = 40）可进行24个月的随访检查。
在12个月时，低度近视组58%（N = 30）的眼睛等效球镜度显验光在预期屈光度的0.50D范围内，中度近视组为50%（N = 17），高度近视组为29%（N = 【此处原文有误，应为7】）。低度近视组87%（N = 45）、中度近视组79%（N = 27）和高度近视组67%（N = 16）的眼睛在预期屈光度的1.00D范围内。在12个月时，低度近视组88%（N = 46）、中度近视组68%（N = 23）和高度近视组68%（N = 16）的眼睛裸眼视力达到20/40或更好，而6%（N = 16）的眼睛视力下降，4%（N = 4）的眼睛视力提高两行或更多行Snellen视力。12个月时，低度近视组58%（N = 30）、中度近视组26%（N = 9）和高度近视组33%（N = 8）的眼睛裸眼视力达到20/20或更好；低度近视组71%（N = 37）、中度近视组39%（N = 13）和高度近视组42%（N = 10）的眼睛裸眼视力达到20/25或更好。12个月时，低度近视组31%（N = 16）、中度近视组38%（N = 13）和基线高度近视组67%（N = 16）检测到过矫（>0.25D），低度和高度近视组之间存在统计学显著差异。
在所有组中，PRK安全性良好，无重大并发症；在矫正超过8.0D（平均-9.40±1.13D）的高度近视组中，该手术在1年时的可预测性仅比低度和中度近视组略低。
