目的:探讨532nm波段激光不同光剂量参数对眼底组织的损伤特点及损伤阈值.方法:以新西兰兔为实验对象,532nm连续激光照射眼底,眼底光斑直径1.5mm～2.5mm,功率密度从500mW/cm2～2400mW/cm2,照射时间100s～300s,每组参数10个光斑.在照射后1h和24h进行眼底观察和荧光眼底造影,计算三种照射时间情况下视网膜的损伤阈值.结果:在照射后第1h,功率密度为902mW/cm2,照射时间300s开始出现视网膜灰色改变,病灶范围接近照光面积,在24h后颜色微加重.随着照光剂量的增加,在功率密度达1479mW/cm2,照射时间300s,照射后1h出现视网膜灰白色改变,在24h后出现脉络膜出血;而且随着照光剂量的增加,病灶范围扩大越明显,出血量越多.随着照光剂量的减少,当功率密度1003mW/cm2,照射时间200s时,在照光后1h眼底没有改变,24h出现视网膜灰白色改变,面积接近照光面积;光剂量降低到1002mW/cm2,照射时间100s时,在24h才出现视网膜灰白色改变,变化的视网膜范围小于照光面积.统计学计算在照射时间为300s、200s和100s,照光后1h视网膜损伤阈值分别为911.15628mW/cm2,1167.64770mW/cm2,1513.89832mW/cm2,24h视网膜损伤阈值分别为827.09664mW/cm2,1003.73143mW/cm2,1154.17863mW/cm2.结论:在光线照射后24h之内,视网膜损伤是一个逐渐增强的过程.从视网膜没有明显可见改变到视网膜出现灰白色可见损伤,变化范围从小于照光面积到接近照光面积,甚至超过照光面积,并出现脉络膜出血,出血面积随着照光剂量的增加而范围变大.相同能量密度的光剂量对视网膜损伤轻重取决于激光的功率密度.

Objective: To observe the biological effect and to calculate the damage threshold on the retina and choroid by 532 nm consecutive wavelength. Method: The Fundus of the New Zealand's rabbits were irradiated by 532 nm consecutive laser, the irradiation of the size were 1.5mm～2.5 mm, the power density was 500mW/ cm~2～2400 mW/ cm~2 and the duration of irradiation 100 s～300 s. Fundus photograph and fluorescein angiography were performed 1 hour and 24 hour after the irradiation to determine the retinal threshold and the characteristics of the retinal damage at different energy of the irradiance. Results: At the circumstance of energy density 902 mW/ cm~2 and the irradiation duration 300 s, the irradiated retina appeared grayish which size was similar to the irradiation1 hour after the exposure, and the color of the lesion became deeper 24h later. Until the irradiance power density rised to 1479 mW/ cm~2 and the duration was 300 s, the irradiated area became grayish and whitish 1 hour after the irradiation and the