Department of Ophthalmology, Putuo Hospital, Shanghai University of Chinese Traditional Medicine, No, 164, Lanxi Road, Shanghai (200062), China.
BMC Ophthalmol. 2014 Jan 21;14:8. doi: 10.1186/1471-2415-14-8.
A new procedure to correct myopia that does not disturb the cornea in the optical zone and avoids injuring the corneal epithelium could be a key advance in corneal refractive surgery. The aim of this study is to observe the refractive change in the adult rabbits undergoing femtosecond laser-assisted multilayer intrastromal ablation in the mid-periphery of the cornea without injury of epithelium.
The right eyes of 8 New Zealand White adult rabbits were used for the experiments. A 60-kHz femtosecond laser delivery system was used, and three lamellar layers of laser pulses were focused starting at a corneal depth of 180 μm and ending at 90 μm from the surface, with each successive layer placed 45 μm anterior to the previous layer. In the interface of the applanation contact lens cone, a 6-mm diameter aluminum circle was placed at the center to block the laser, limiting ablation to the mid-periphery of the cornea. The laser settings were as follows: spot/line separation, 10 μm; diameter, 8.0 mm; energy for ablating the stroma, 1.3 μJ. An authorefractor was used to assess the manifest refraction.
Mean spherical equivalent (SE) (mean ± SD, SD: standard deviation) was significantly increased at postoperative week 1 (1.67 ± 0.26 D, p < 0.0001), month 1 (1.65 ± 0.23 D, p < 0.0001), and month 3 (1.60 ± 0.22 D, p < 0.0001) compared to baseline (0.68 ± 0.27 D). Mean spherical equivalent showed no significant change between postoperative week 1 and month 3 (p = 0.1168).
Femtosecond laser-assisted multilayer corneal intrastromal ablation in the mid-periphery may cause a consequent hyperopic shift with no refractive regression.
一种新的近视矫正手术方法，不干扰光学区的角膜，避免损伤角膜上皮，可能是角膜屈光手术的一个关键进展。本研究旨在观察在不损伤上皮的情况下，用飞秒激光辅助角膜中层基质内多层光爆破术矫正成年新西兰白兔的屈光度。
对 8 只新西兰大白兔右眼进行实验。采用 60kHz 飞秒激光传输系统，在角膜深度 180μm 处开始，在距表面 90μm 处结束，共聚焦三束激光脉冲，每束激光脉冲位于前一层的前 45μm 处。在压平接触镜锥体的界面处，中心放置一个 6mm 直径的铝圈以阻挡激光，限制光爆破仅限于角膜的中周部。激光参数设置为：光斑/线间隔 10μm，直径 8.0mm，基质消融能量 1.3μJ。采用自动折射仪评估眼前节的屈光度。
术后 1 周（1.67±0.26D，p＜0.0001）、1 个月（1.65±0.23D，p＜0.0001）和 3 个月（1.60±0.22D，p＜0.0001）平均等效球镜（SE）（均数±标准差，SD：标准差）与基线值（0.68±0.27D）相比显著增加。术后 1 周与 3 个月时 SE 相比差异无统计学意义（p=0.1168）。
飞秒激光辅助角膜中层基质内多层光爆破术可导致中周部角膜产生连续的远视漂移，无屈光回退。
