Investigation On Multifocal Electroretinogram Of Myopic And Normal Eyes

Objective: In order to characterize and evaluate the retinal function of myopia, we analyzed and compared a group of myopic eyes and normal eyes by using multifocal electroretinogram (mERG).Methods: mERG was detected by Vision monitor made by Metro vision of France. Data from 90 myopic eyes(74 myopic cases) was analyzed and compared with those 30 normal eyes(18 normal cases). All the data were involved in the amplitude densities and latencies of mERG in 5 rings. Myopic eyes were divided into three groups according to the degree of refractive errors which were low myopia,moderate myopia and high myopia.Results: 1.The Studies showed that signals of the normal eyes at 1 ring had the highest amplitude densities, which decreased rapidly followed by the increase of eccentricity, while the latencies was the shortest at 1 ring and delayed followed by the increase of eccentricity gradually.2.Myopic eyes had the highest amplitude densities which was lower than normal eyes at 1 ring, that decreased rapidly followed by the increase of eccentricity. No obvious relationship between latencies and eccentricity had been confirmed.3. The difference between the myopic eyes and the normal eyes was dicussed bellowed: (1) The amplitude densities had statistically significant difference between the moderate myopic eyes, high myopic eyes and the normal eyes, while there was no statistically significant difference between low myopic eyes and the normal eyes at the amplitude densities. (2) The latencies had statistically significant difference between the moderate myopic eyes, high myopic eyes and the normal eyes at 1 ring, while there was no statistically significant difference at other rings. There was no statistically significant difference between low myopic eyes and the normal eyes at the latencies.(3) There was statistically significant difference between low myopic eyes, moderate myopic eyes and high myopic eyes at the amplitude densities. There was no statistically significant difference among them at the latencies.Conclusions: 1. There was the highest amplitude densities and the shortest latencies in 1 ring. The amplitude densities decreased rapidly, while the latencies delayed gradually followed by the increase of eccentricity. 2. Myopic eyes had the highest amplitude densities which was lower than normal eyes decreased rapidly followed by the increase of eccentricity. No obvious relationship between latencies and eccentricity had been confirmed. 3.There is a negative correlation between the diopter and the amplitude densities of mERG. 4.The moderate myopic eyes and the high myopic eyes had lower amplitude densities than the normal eyes in mERG, while the latencies was longer than the normal eyes at 1 ring. There was no change between the low myopic eyes and the normal eyes at the amplitude densities and the latencies.