The fundamental transverse mode (TEM00 T is preferable for experimental and theoretical study on the laser-induced retinal injury effect, for it can produce the minimal retinal image and establish the most strict laser safety standards. But actually lasers with higher order mode were frequently used in both earlier and recent studies. Generally higher order mode leads to larger retinal spot size and so higher damage threshold, but there are few quantitative analyses on this problem. In this paper, a four-surface schematic eye model is established for human and macaque. The propagation of 532-nm laser in schematic eye is analyzed by the ABCD law of Gaussian optics. It is shown that retinal spot size increases with laser transverse mode order. For relative lower mode order, the retinal spot diameter will not exceed the minimum laser-induced retinal lesion (25 ~ 30 μm in diameter), and so has little effect on retinal damage threshold. While for higher order mode, the larger retinal spot requires more energy to induce injury and so the damage threshold increases. When beam divergence is lowered, the retinal spot size decreases correspondingly, so the effect of mode order can be compensated. The retinal spot size of macaque is slightly smaller than that of human and the ratio between them is independent of mode order. We conclude that the laser mode order has significant influence on retinal spot size but limited influence on the retinal injury effect.

目的: 建立脉冲1 064 nm Nd:YAG激光致视网膜出血性损伤及非出血性损伤动物模型, 为治疗药物评价提供技术基础。方法: 应用自由振荡脉冲及调Q脉冲1 064 nm激光照射青紫蓝灰兔视网膜, 通过在光路中加入透镜获得直径200 μm眼底光斑, 加入衰减片改变角膜入射激光能量。照射即刻对损伤应用检眼镜进行实时观察, 并用眼底相机在损伤后不同时间进行照相。结果: 视网膜典型非出血损伤参数为脉冲宽度85 μs, 激光能量15.0 mJ, 光斑直径200 μm, 损伤1小时局部出现水肿或渗出, 损伤后1天水肿及渗出明显, 损伤后3天水肿及渗出部分消退; 损伤后7天水肿及渗出已完全消退; 典型出血损伤参数为脉冲宽度20 ns, 激光能量2.4 mJ, 光斑直径200 μm, 损伤后1小时损伤斑清晰, 环状出血颜色鲜红; 损伤后1天出现水肿, 环状出血颜色稍淡; 损伤后3天损伤斑水肿及渗出仍较明显, 出血颜色明显变淡; 损伤后7天水肿及渗出消退, 边缘出血吸收、区域缩小。结论: 成功建立了Nd:YAG激光致视网膜出血和非出血损伤动物模型, 可用于药物筛选及评价。

采用高功率电磁波直接辐照家免全身后,即刻分别测试家兔的视网膜电流图(Electro-retinogram,ERG);随后即刻取材,包埋固定,分别在光学显微镜和透射电镜下观察其视觉器官的组织结构.结果表明,高场强的高功率微波辐照可造成家兔眼视网膜组织的即刻损伤,对家兔视觉电生理功能可产生明显的抑制作用,其作用强度与辐照剂量和辐照时间存在一定的量效、时效关系.

沙尘衰减对高功率微波在大气中的传播有较大的影响,通过结合干沙的复介电常数公式与Ray提出的水的介电常数公式给出了沙尘衰减的计算模型,利用该模型分析了爆炸沙尘、车扬沙尘和自然沙尘的衰减.根据数值计算结果,仿真了不同含水量的沙尘衰减率随微波频率的变化,结果表明:在频率不是太高时,自然风沙和车扬沙尘对微波传输的影响不大,而爆炸环境下的沙尘衰减必须要考虑;沙尘衰减随水含量的增加而明显上升,此效应在较小差别的20%～30%水含量中处于饱和状态,这说明在高湿度热带地区的沙尘衰减将比沙漠和半沙漠地区的衰减大得多.