聚焦Tm激光与眼角膜热作用的研究

Study of thermal effects for interaction focused Tm laser with cornea

随着全世界老龄化的加重,老年人的生活质量越来越受到重视,而老花眼(老视)是每个人步入中年都要面对的视觉问题。激光热成型术(LTK)在矫正老视的临床中占有重要的应用前景。为了研究新型Tm激光与角膜热作用的生物学效果,采用有限元方法模拟了聚焦Tm激光各参数作用下角膜组织内温度场的分布。模拟结果表明激光有效穿透深度与激光功率密度和时间都是正向相关,而与能量密度的正向相关性较差激光作用时间越长,角膜组织中的温度梯度越小。实验上,采用猪眼角膜为实验对象,在不同激光功率密度作用下,利用病理切片观察角膜的变化,发现功率密度在86W/cm2至98W/cm2,能量密度在172J/cm2至294J/cm2范围内,角膜组织有合适的穿透深度350μm至425μm和明显的力学变化,能较好实现角膜中胶原的热收缩。

Along with aggravation of ageing in all worlds, life quality about the elderly is more and more regarded. However, Presbyopia （hyperopia） that everyone must face into the middle - aged visual problems. Laser thermal keratoplasty （LTK） will has an important application future for correction of hyperopia. In order to investigate biology effects of thermal interaction new type Tm laser with cornea, temperature field distribution that interaction different parameters focused Tm laser with cornea in the cornea was simulated with the finite element method. Simulated results indicated that laser effective penetrated depth with laser power density and time are positive correlation, but with energy density of positive correlation was not good; time of inaction laser with cornea was longer, temperature grads was smaller in cornea. In the experiment, pig＇s eye cornea was used as experiment objects. After several laser power density radiated, changes of cornea were observed with pathological photos, the results indicated that light have a appropriate penetrate depth in cornea： 350 - 425μm and visible dynam changes under interaction laser power density is from 86 to 98W/cm^2 and energy density is from 172 - 294J/cm^2, it can better achieve thermal shrinking of collagen in the cornea.