经瞳孔温热疗法对正常兔眼视网膜脉络膜的影响

Histopathology findings in pigmented and nonpigmented rabbits after transpupillary thermotherapy

目的 探讨影响经瞳孔温热疗法(TTT)治疗效果的因素。方法 健康成年日本大耳白兔8只、青紫兰兔12只分为3组,麻醉、散瞳并安放全视网膜镜,行TTT。结果 光斑直径为1.2 mm ,暴露时间为1分钟时,正常白兔进行阈值TTT所需的激光功率为12 0 0 m W,正常灰兔进行阈值TTT所需的激光功率为110 m W;随激光功率的增加视网膜出现颜色改变的同时,光镜下亦出现相应的改变;照射时给眼球一定的压力,使脉络膜循环发生障碍,会加重激光对视网膜的损坏。结论 TTT是一种阈值治疗,阈值上治疗可引起兔眼视网膜组织的不可逆损伤。眼底色素含量与脉络膜循环状态是影响阈值功率选择的重要因素。

Objective To evaluate the factors influencing effectiveness of transpupillary thermotherapy (TTT) by animal experiments. Methods 8 nonpigmented rabbits and 12 pigmented rabbits were divided into 3 groups, anaesthetized, dilated pupils and TTT was performed. Results When spot size was 1.2mm, laser duration was 1 minute, the threshold powers of the nonpigmented rabbits and pigmented rabbits were 1200mW and 110mW respectively, The higher power of the TTT, the more visible effects on the retina of the rabbits were observed. If the eye was pressurized by handheld contact lens to decrease the choroidal blood flow, the laser damage to the retina had been aggravated. Conclusions TTT with surperthreshold power causes the irrecoverable damage to retina. The present study demonstrates that thereis closed correlation between threshold power and pigment, choroidal blood flow.