Kim J H, Sah W J, Park C K, Hahn T W, Kim M S
Department of Ophthalmology, Kangnam St. Mary's Hospital, Catholic University Medical College, Seoul, Korea.
Ophthalmic Surg Lasers. 1996 May;27(5 Suppl):S435-9.
Myopic photorefractive keratectomy (PRK) using the 193 nm excimer laser is an effective and precise surgical procedure to correct myopia, but not without complications, such as corneal haze, over- or undercorrection, halo, glare, and myopic regression. Among these, myopic regression, which can reduce uncorrected visual acuity, is the most common and progressive long-term complication.
We evaluated 228 eyes that received successful myopic PRK with the Summit excimer laser (ExciMed UV 200LA, 5.0 mm optical zone) and followed up more than three years at Kangnam St. Mary's hospital. Two hundred twenty eight eyes were divided into 3 groups according to the degree of preoperative myopia and correction: Group I, 79 eyes of moderate myopia (-2.25 to-6.75 diopters [D]) with full correction; Group II, 110 eyes of high myopia (-7.00 to -12.50 D) with full correction by two-zone ablation; Group III, 29 eyes of high myopia (-7.00 to -12.00 D) with partial correction of 6.00 D. Retrospective analysis of the data was performed with statistical evaluation of the incidence of myopic regression, regression formula, coefficient of parameters, and cumulative hazard of regression in each group.
An incidence of myopic regression greater than 1.00 D was noted in 40.5%, 83.3%, and 18.2% of patients in Group I, II, and III, respectively. The regression formula obtained from the repeated measure ANOVA was Y = 2.13 -0.47 InX, Y = 3.02 -0.82 InX, and Y = 3.69 -0.50 InX, in Group I, II, and III, respectively. The amount of correction was a statistically significant correlation factor to the myopic regression (Pearson's correlation coefficient = 0.78, P < 0.001). The amount of preoperative myopia may act as a negative correlation factor to the myopic regression. According to the Kaplan-Meyer survival table, the cumulative correlation hazard was significantly higher in high myopia with full correction than in moderate myopia with full correction.
Our results indicated that the incidence and amount of myopic regression have a tendency to be dependent on the amount of correction, but may be reduced as the preoperative myopia increases, if the amount of correction is the same. A longer term and more detailed study of PRK using a 6.0 mm optical zone will be needed to determine how the amount of preoperative myopia and would profiles affect the myopic regression.
使用193纳米准分子激光进行的近视性光性屈光性角膜切削术（PRK）是一种有效且精确的矫正近视的外科手术，但并非没有并发症，如角膜混浊、矫正过度或不足、光晕、眩光和近视回退。其中，可降低未矫正视力的近视回退是最常见且渐进性的长期并发症。
我们评估了在江南圣母医院接受Summit准分子激光（ExciMed UV 200LA，5.0毫米光学区）成功进行近视PRK且随访超过三年的228只眼。根据术前近视程度和矫正情况将228只眼分为3组：第一组，79只中度近视（-2.25至-6.75屈光度[D]）且完全矫正的眼睛；第二组，110只高度近视（-7.00至-12.50 D）通过双区消融进行完全矫正的眼睛；第三组，29只高度近视（-7.00至-12.00 D）且部分矫正6.00 D的眼睛。对数据进行回顾性分析，并对每组近视回退的发生率、回退公式、参数系数和累积回退风险进行统计学评估。
第一组、第二组和第三组患者中近视回退大于1.00 D的发生率分别为40.5%、83.3%和18.2%。通过重复测量方差分析得到的回退公式在第一组、第二组和第三组中分别为Y = 2.13 - 0.47 InX、Y = 3.02 - 0.82 InX和Y = 3.69 - 0.50 InX。矫正量是与近视回退具有统计学显著相关性的因素（Pearson相关系数 = 0.78，P < 0.001）。术前近视量可能是与近视回退呈负相关的因素。根据Kaplan - Meyer生存表，完全矫正的高度近视患者的累积相关风险显著高于完全矫正的中度近视患者。
我们的结果表明，近视回退的发生率和程度倾向于依赖矫正量，但如果矫正量相同，随着术前近视增加可能会降低。需要使用6.0毫米光学区对PRK进行更长期、更详细的研究，以确定术前近视量和屈光度分布如何影响近视回退。
