O'Brart D P, Corbett M C, Verma S, Heacock G, Oliver K M, Lohmann C P, Kerr Muir M G, Marshall J
Department of Ophthalmology, United Medical School, St. Thomas' Hospital, London.
J Refract Surg. 1996 Jan-Feb;12(1):50-60. doi: 10.3928/1081-597X-19960101-12.
To investigate the effects of the ablation diameter, depth, and edge contour on the outcome of excimer laser photorefractive keratectomy (PRK).
A prospective study was conducted in which 60 patients (60 eyes) were randomly allocated to 5.00-mm, 6.00-mm, or 5.00 to 6.00-mm multizone treatment groups. All eyes underwent a -6.00 diopter (D) correction using a Summit Omnimed excimer laser.
In eyes treated with 6.00-mm diameter zones, the initial hyperopic shift was reduced, with significant differences at 1 and 4 weeks (p < 0.01). At 6 and 12 months, the refractive changes were closer to the intended correction with 6.00-mm diameters. The predictability of PRK was improved with 6.00-mm zones, with a significant reduction in variance of the refractive changes, at all stages postoperatively (p < 0.05 to p < 0.001). Objective measurements of haze were significantly less at 1, 3, and 6 months with 6.00-mm ablations (p < 0.05). There were no differences between the 5.00-mm and the 5.00- to 6.00-mm multizone groups. Computerized measurements of "night" halo were significantly smaller in the 6.00-mm treatment group at 1 week and 1 month (p < 0.05). At 12 months, two patients treated with 5.00-mm zones and three with the 5.00- to 6.00-mm multizone complained of severe night vision disturbances. No 6.00-mm eyes were similarly affected.
Treatment with a 6.00-mm spherical ablation diameter produced less initial overcorrection, improved predictability, and was associated with a reduction in postoperative halos and night vision disturbances. Creating a superficial blend zone with a 5.00- to 6.00-mm multizone treatment had no beneficial effect on the outcome.
研究准分子激光屈光性角膜切削术（PRK）中消融直径、深度和边缘轮廓对手术效果的影响。
进行一项前瞻性研究，将60例患者（60只眼）随机分为5.00毫米、6.00毫米或5.00至6.00毫米多区治疗组。所有眼睛均使用Summit Omnimed准分子激光进行-6.00屈光度（D）的矫正。
在直径为6.00毫米区域治疗的眼睛中，初始远视偏移减少，在1周和4周时存在显著差异（p < 0.01）。在6个月和12个月时，直径为6.00毫米的屈光变化更接近预期矫正。6.00毫米区域可提高PRK的可预测性，术后各阶段屈光变化的方差显著降低（p < 0.05至p < 0.001）。6.00毫米消融在1、3和6个月时客观测量的 haze 明显更少（p < 0.05）。5.00毫米组和5.00至6.00毫米多区组之间没有差异。6.00毫米治疗组在1周和1个月时“夜间”光晕的计算机测量值明显更小（p < 0.05）。在12个月时，2例接受5.00毫米区域治疗的患者和3例接受5.00至6.00毫米多区治疗的患者抱怨有严重的夜间视力障碍。没有6.00毫米区域治疗的眼睛受到类似影响。
6.00毫米的球形消融直径治疗产生的初始过度矫正较少，可提高可预测性，并与术后光晕和夜间视力障碍的减少有关。采用5.00至6.00毫米多区治疗创建浅表融合区对手术效果没有有益影响。
