微型角膜刀制作超薄角膜瓣的实验研究

The experimental study of ultra-thin corneal flaps made by microkeratome

目的研究KM_5000D微型角膜刀制作超薄角膜瓣的技术。方法设计制作超薄角膜瓣的自动旋转型KM_5000D微型角膜刀成形系统包括微型切割器、双电机动力装置和控制箱部件。以此成形系统对新鲜离体猪眼80眼、离体人眼10眼和在体兔眼12眼进行超薄角膜瓣的制作,观察运刀情况,角膜瓣厚度、直径以及瓣异常的发生率;离体人眼角膜瓣标本在光镜和扫描电镜下观察切面和边缘形态。结果实验中,负压保持眼压稳定在65 mmHg。离体猪眼角膜瓣厚度和直径分别为(87.85±4.64)μm和(8.8±0.42)mm,瓣异常发生率18.75%。离体人眼角膜瓣厚度和直径分别为(86.4±5.13)μm和(7.5±0.55)mm,瓣异常发生率20%。在体兔角膜瓣厚度和直径分别为(62.08±3.70)μm和(7.96±0.30)mm,瓣异常发生率16.67%。离体猪眼、离体人眼和在体兔眼的运刀顺畅比率分别为88.75%,80.0%和83.33%。离体人眼角膜瓣光镜检查显示其保持了角膜上皮、前弹力层和前部少许基质,扫描电镜检测显示切面光滑度和边缘整齐性良好。结论KM_5000D微型角膜刀制作超薄角膜瓣安全有效,预测性、稳定性良好。可应用于超薄角膜瓣LASIK手术的临床研究。

Objective To develop the technique of making ultrathin corneal flaps with KM-5000D microkeratome. Methods KM- 5000D microkeratome system for ultra-thin corneal flaps was designed and manufactured. Ultra-thin corneal flaps were made by KM-5000D microkeratome on 80 fresh pig eyes, 10 human eyes in vitro and 12 rabbit eyes in vivo. The facility of the microkeratome, the size and thickness of the flaps and the rates of abnormal flaps were observed. The samples of the human corneal flaps were examined under light microscope and scanning electronic microscope. Results The automatically rotating KM-5000D microkeratome system comprised three parts： micro-cut system, double eleetronic dynamic device and control panel. Performing on pig eyes, human eyes and rabbit eyes, the vaccum was able to keep the intraocular pressure stable at 65 mmHg. The thickness and size of flaps in pig eyes were 87.85 ± 4.64μm and 8.8 ± 0.42 mm,86.4 ±5.13 μm and 7.5 ± 0.55 mm in human eyes, 62.08± 3.70 μm and 7.96 ± 0.30 mm in rabbit eyes. The percentage of the abnormal flaps was 18.75%, 20% and 16.67% respectively. The rates of smooth performance with the keratome were 88.75% , 80.0% and 83.33% respectively. The samples of the human corneal flaps comprised epithelium, Bowman＇s membrane and anterior stroma under light microscopic examination. The margin of the flap was smooth and in good order under scanning electronic microscopic examination. Conclusions It is safe, effective and predictable to make ultra-thin corneal flaps by KM-5000D microkeratome. Making ultra-thin corneal flaps for LASIK could be under clinical studies.