Carones F, Brancato R, Morico A, Venturi E, Gobbi P G
Department of Ophthalmology and Visual Sciences, Scientific Institute San Raffaele Hospital, University of Milan, Italy.
Ophthalmic Surg Lasers. 1996 May;27(5 Suppl):S458-65.
The aim of this study was to evaluate the results of myopic excimer laser photorefractive keratectomy (PRK) performed using three different ablation approaches.
Using the Apex excimer laser (Summit Technology, Inc., Waltham MA), we have treated 75 eyes. Twenty-five of them were treated by a single ablation zone (SA, 6.5 mm diameter) to correct myopia of -4.50 +/- 2.10 D (mean +/- SD); 25 eyes underwent PRK for the correction of myopia of -4.98 +/- 2.17 D using a multipass multizone technique (MP, 3 zones); and 25 eyes were corrected for myopia of -5.03 +/- 1.98 D using new software which enables the creation of three ablation zones in a single-pass fashion (MZ).
Mean refractive error (+/-SD) at the first post-operative month was +1.34 +/- 1.00 D for SA, +1.78 +/- 1.49 D for MP, and +0.90 +/- 0.75 D for MZ. Eyes treated by MZ had significantly better uncorrected visual acuity than those treated by SA (P=0.04). Corneal topography revealed a central island in 14 eyes (56%) of those treated by SA and 2 eyes (8%) of those treated by MZ, but in no eyes treated by MP. Six months after treatment, mean refractive error was +0.28 +/- 0.75 D for SA, +0.36 +/- 0.92 D for MP, and - 0.07 +/- 0.77 D for MZ.
MZ ablation induced less hyperopic shift at 1 month, thus leading to a faster visual recovery and better uncorrected visual acuity. MP and MZ ablations proved effective in preventing central island formation, thus inducing less visual disturbances than SA ablations. These results suggest that MZ ablation may be preferable to the other techniques in performing myopic PRK.
本研究旨在评估采用三种不同消融方法进行的近视准分子激光屈光性角膜切削术（PRK）的效果。
使用Apex准分子激光（Summit Technology公司，马萨诸塞州沃尔瑟姆），我们治疗了75只眼睛。其中25只眼睛采用单个消融区（SA，直径6.5毫米）进行治疗，以矫正-4.50±2.10 D（平均值±标准差）的近视；25只眼睛采用多程多区技术（MP，3个区）进行PRK以矫正-4.98±2.17 D的近视；25只眼睛采用新软件以单程方式创建三个消融区（MZ）来矫正-5.03±1.98 D的近视。
术后第一个月，SA组的平均屈光不正（±标准差）为+1.34±1.00 D，MP组为+1.78±1.49 D，MZ组为+0.90±0.75 D。MZ组治疗的眼睛的裸眼视力明显优于SA组治疗的眼睛（P = 0.04）。角膜地形图显示，SA组治疗的眼睛中有14只（56%）出现中央岛，MZ组治疗的眼睛中有2只（8%）出现中央岛，而MP组治疗的眼睛中未出现中央岛。治疗六个月后，SA组的平均屈光不正为+0.28±0.75 D，MP组为+0.36±0.92 D，MZ组为-0.07±0.77 D。
MZ消融在1个月时引起的远视性偏移较小，从而导致更快的视力恢复和更好的裸眼视力。MP和MZ消融被证明可有效防止中央岛形成，因此与SA消融相比引起的视觉干扰更少。这些结果表明，在进行近视PRK时，MZ消融可能比其他技术更可取。
