不同方式飞秒激光制瓣对兔眼角膜生物力学的影响

Exprimental study on corneal biomechanics after customize corneal flap with femtosecond laser

目的应用角膜生物力学分析仪CorvisST研究飞秒激光设计制作角膜瓣后对兔眼角膜生物力学的影响。方法实验研究。于2014年11月在南昌大学第三附属医院眼科筛选出16只大白兔，随机分成A、B两组各8只。使用iFS150飞秒激光制作角膜瓣。A组设置飞秒激光边切角度70°，其中A1组为有眼，瓣蒂位于上方，A2组为左眼，瓣蒂位于鼻侧；B组设置飞秒激光边切角度120°，B1组为右眼，瓣蒂位于上方，B2组为左眼，瓣蒂位于鼻侧。所有兔眼均设置瓣厚度为100μm，直径8．5mm。于术前、术后1周、1个月、3个月行CorvisST检查，对兔眼角膜制瓣术后3个月与术前CorvisST测量的生物力学相关参数进行分析。结果各组手术后3个月的第一次压平时间（1-time）较术前缩短，差异均具有统计学意义（P〈0．05），DA较术前增加，差异均具有统计学意义（P〈0．05）。A2组术后3个月的第二次压平时间（2-time）较术前延长，差异具有统计学意义（P〈0．05），B1组术后3个月的PD较术前增加，差异具有统计学意义（P〈0．05）。各组之间相比术前与术后3个月的1-time和角膜变形幅度差异均无统计学意义（P〉0．05）。结论飞秒激光制作角膜瓣后早期角膜生物力学特性有一定的下降，下降的程度与角膜瓣边切角度和蒂的方位没有明显相关性。

Objective To investigate impact on corneal biomechanics after corneal flap with fetmosecond laser in different side cut angle and flap hinge. Methods Sixteen New Zealand white rabbits were divided in group A and group B （8 rabbits in each group）, then were used for corneal flap preparation with femtosecond laser. Right eye in group A was divide in subgroup A1 with side cut angle of 70 and superior flap hinge, left eye was divide in subgroup A2 with side cut angle of 70 and nasal flap hinge. Right eye in group B was divide in subgroup B1 with side cut angle of 120 and superior flap hinge, left eye was divide in subgroup B2 with side cut angle of 120 and nasal flap hinge. All corneal thickness was set to be 100 μm with diameter of 8.5mm. In the follow-up on pre-operation and 1 week, 1 month, 3 months after operation, Corvis ST were tested. Mean first and second applanation time, mean first and second applanation length, mean first and second applanation velocity, radius of curvatur, peak distance and deflection amplitudes （DA） recorded by Corvis ST were analyzed. Results First applanation time were significantly decreased in four groups 3 months after operation. DA were significantly increased, Second applanation time was significantly increased in subgroup A2, peak distance was significantly increased in subgroup B1. There were no significant difference preoperatively and 3 months postoperatively on First applanation time and DA among groups. Conclusions In the vivo rabbit experiment, decrease is demonstrated in corneal biomechanics early after femtosecond laser for production of corneal flap regardless of superior or nasal flap hinge.