飞秒激光预切制作角膜内皮瓣的质量评估

目的　评估飞秒激光制备的角膜内皮瓣的质量。方法　取９只供体角膜用飞秒激光切削制作８．５ｍｍ直径的角膜内皮瓣。预留角膜内皮瓣厚度大于１４０μｍ，避免切穿角膜。激光切削后将整个角膜放回Ｄｅｘｓｏｌ液保存。预切前后Ａ超测量角膜厚度。预切前、预切后３ｄ内用角膜内皮镜观察角膜内皮细胞数量和形态。预切后３～７ｄ做台盼蓝染色观察内皮细胞活性。结果　测得的角膜内皮瓣厚度为（２３７±６５）μｍ，实际角膜内皮瓣厚度与预设偏差－１９～１４０（３５±６５）μｍ。预切前角膜内皮细胞密度（３２１５±２２５）ｍｍ－２，预切后１ｄ角膜内皮细胞密度损失７．２％（Ｐ＝０．０３），预切后３ｄ损失３．１％（Ｐ＝０．４０）。预切后２ｄ有６片角膜内皮细胞形态清晰，预切后３ｄ仅有２片角膜内皮细胞形态清晰。中期保存３～７ｄ有４片角膜出现较多核蓝染细胞。结论　飞秒激光制备的角膜内皮瓣厚度适宜；预切后中期保存的供体内皮瓣应尽快用于手术。

Evaluation of corneal endothelial flap pre-cut by femtosecond laser

Objective To evaluate the corneal endothelial flap pre-cut by femtosecond laser. Methods 9-situ removal corneas preserved in Dexsol before surgery. FS200 femtosecond laser cutting corneal stroma produced the 8. 5 mm diameter corneal flap. The preserved corneal endothelial flap thickness was more than 140 ym to avoid perforation. After laser cutting, the entire cornea was put back in Dexsol. The comeal thickness was measured before and after pre-cut using type A ultrasonic thickness measurement instrument. The corneal endothelial cell density was measured and the cell morphology was observed before and within 3 days after pre-cut using comeal endothelial nucroscope. The endothelial cell activity was tested by trypan blue in 7 days after the pre-cut. Results The mean corneal endothelial flap thickness was (237 + 65 ) ym. The range of deviation between obtained and preset was - 19 - 140 ( 35 + 65 ) ym. The corneal endothelial cell density was ( 3215 + 225 ) mm -2 At the I d after pre-cut the endothelial cell loss was 7. 2% ( P = 0. 03 ) . At the 2 d after pre-cut the endothelial cell loss was 3. 1% (P = 0. 40) . Six piece of corneal endothelial cells morphology were clear at 2 days after pre-cut. But only 2 piece of corneal endothelial cells morphology was clear at 3 days after pre-cut. Many nuclei of 4 corneas were stained by trypan blue in 7 days after the pre-cut. Conclusion The thickness of corneal endothelial flap made by femtosecond laser is appropriate. The pre-cut corneal endothelial flap should be used for surgery as soon as possible.