Calculation And Experiments On Retina Injury Of Different Laser Transverse Modes

The most part of laser eye injuries occur in future warfare will be high-order laser eye injuries, so deep study on laser eye injury of different mode is significant to the manufacture and appraisement of laser weapons.It useed adaxial optics to set up an eye model which can adjust focus. On the basis of that model, it used Gaussian beam ABCD matrix and nested Gaussian beam to calculate the retina image. Result: under certain dioptriccal state, the size of retina image largen according to the change of radiation distance; bigger beam divergence and higher mode will make bigger retina image. Furthermore, to the nested Gaussian beam , the proportion between corneal radiance intensity and retina image density has nothing with mode when the beam enter the pupil fully, that is to say that ED-50 of different mode can be united in the retina injury threshold of TEM 00.The fundus of the New Zealand's rabbits were irradiated by pulsed Nd:YAG laser which exports 1064nm and 532nm. The two sides eyes of rabbits need to receive radiation of different mode to reduce biological diversity. Counting the number of injured spot appeared in 1 hour at two exposure near by the threshold set before. The circumstance of retina injury was shoot and the sample was sliced up. Resultl: Under certain injure probability , high mode laser needs much higher energy than low mode. Immediateness observation after irradiation by fundus camera showed chrysanthemum haemorrhage which was absorbed a little after 24 hours. In microscopical examination the damage spot of high mode was bigger than that of low order mode. The place where deformed like hillock and the retinal pigment epithelium there collapsed and decomposed.Conclusion: The retinal image is affected by dioptric state and beam divergence. At same radiation exposure, the retina image of high-order mode is bigger, so it will be more difficult to damage retina for a laser at higher order mode. At same injury probability, the energy of higher order is larger than that of lower order.