Quantitative investigation of early influences of laser photocoagulation on retinal function in diabetic retinopathy / 中华眼底病杂志

ABSTRACT

Objective To investigate the early influences of laser photocoagulation on retinal function in diabetic retinopathy(DR). Methods The multifocal electroretinograms (MERG) of 30 eyes with DR (phase Ⅲ～Ⅳ) were tested with visual evoked response image system IV before,and the 3 rd day and the 7 th day after laser photocoagulation. Results Three days after photocoagulation, the latency of N1 prolonged in the central macula 5? area and superionasal quadrant.The response densities of N1,P1 and N2 markedly reduced, and most significant changes occurred in the central macula 5? area and then in the central 10?area. There were also differences in the changes of the amplitude of N1 and P1 in different quadrants .The changes of visual acuity were positively related to the decrease of amplitudes of N1,P1 and N2 in the macula. Conclusion The reduction of response densities in MERG reveals functional damage in diabetic retina occurring early after photocoagulation.The functional damage in macula induced indirectly by photocoagulation may explain the reduction of visual acuity after panretinal photocoagulation in some degree.