The Observing Of The Effects On Cobayas' Retina By Semi-conductor Laser Shining Through Pupil

Objective By observing the change of electroretinagram(ERG) between pre-experiment and post-experiment and the disforming of retinal after the semiconductor laser shining, it was to estimate the injurying influence on retinal after the shining of different power and different times semiconductor laser. And then a safe power standard will be found for the clinic treatment of amblyopia.Method Ninety Cobayas were chosen no matter male or female. They were divided into five groups in random according to the shining power, namely normal control group A, group B (2mW), group C (3mW), group D (4mW) and group E (5mW). Then except group A, the others were subdivided into team j (one time a day) and team k (two times a day) according to shining times. Every body had been scotopia for 12h, dropped 1.25% Tropicamide-Phenylephrine ophthalmic solution for cycloplegia and then injected 2% Chloral Hydrate into abdominal cavity for anesthesia. After that, the pre-experiment flash electroretinogram (fERG) of cobayas had been made. Then the eyes of cobayas were shined through the pupil by semi-conductor laser sent out from the LL-300 amblyopia apparatus, which the shining power and time were according to the standard of dividing team. Three minutes one time and continued to 30 days. Then the post-experiment fERG was made for everyone as done before. The changing of fERG had been compared. In the end of the experiment, the subjects were killed and their shining eyes were extracted quickly. The half post retinal of eyes were striped and made up specimens in accordance with the different requirements of photomicroscope, electromicroscope and immunohistochemistry test.Result There was statistical difference showing in the flash eletroretinagram in amplitude of a-wave between every group (P=0.01). Among this, the difference between group C and group D seems more obvious (P=0.002). In the same, there was obviously difference between group C and group E (P=0.025). On the contrary, there was no statistical difference in the amplitude of b-wave and N1-P1-wave between every group (P=0.30 and P=0.19). Between different shining power teams there was difference in statistics in the apoptotic index of retinal cell detected by TUNEL (P=0.025). In the same there was difference between them in gray scale detected by Fas(P=0.00). In observation by electronmicroscope, the number of the apomorphosis of retinal cell got more and more while the shining power was above 3mW.Conclusion The different reaction in electrophysiology was found in retinal sensitive cell, which was shown in the ascendance of a-wave in group C but descent in group D and group E. The change of electrophysiology in other parts was not found. It suggested in this experiment that the 2mW shining power of semiconductor laser had little influence on the coboyas'retinal. But in group C, group D and group E, the more shining power, the more injury had been found in morphology.