Multifocal Electroretinography In Diabetic Macular Edema;Correlation With Retinal Thickness And Visual Acuity

Objective: To evaluate multifocal electroretinogram(mfERG) changes in eyes with diabetic macular edema(DME) and investigate any possible correlation with retinal thickness and visual acuity(VA).Methods: 67 eyes of 45 patients who were diagnosed as Diabetic Macular Edema through optometry,fundus color photography,optical coherence tomography and fundus fluorescence angiography(FFA) from May to October 2015 at Department of Ophthalmology in our hospital were examined by Sixty-one scaled hexagon mfERG of Germany RETIScan Multifocal visual electrophysiological examination system,and 31 eyes of 17age-matched normal subjects were accepted the same examinations except the FFA. To analyze the multifocal electroretinogram(mfERG) changes in the two groups and investigate any possible correlation with retinal thickness and VA.Results: Mean BCVA of DME group was(0.75±0.46)LogMAR.The mean central macular retinal thickness( CMT) of normal group was261.68±15.94 micrometers(μm)ranging from 234 to 293μm, and the DME group was 431.79±131.61μm ranging from 242 to701μm, there was statistically significant differences in mean CMT compared with normal group(t=10.416,P=0.000), The differences in mean CMT of DME and normal group between male and female was no statistical significance(P>0.05). There were significant differences in all mfERG parameters in five-ring regions of the retina between the DME and normal groups. Therewas a significant inverse association between BCVA and mean CMT, the association between BCVA and amplitude density and latency of P1 and N1 latency in mfERG parameters in one ring was significant. But the correlation between BCVA and other mfERG parameters in one ring was no statistical significance.The correlation between mean CMT and mfERG parameters in one ring was also no statistical significance.Conclusions: The mean CMT of patiens with DME was thicker than that of normal subjects,and it was concluded that patients with DME had significantly abnormal mfERG responses,i.e.,decreased amplitudes and delayed latencies. Visual acuity of patiens with DME was correlated with mean CMT, P1-waves and N1-waves parameters of mfERG in one ring. A combination of Visual acuity,OCT and FFA could comprehensively evaluate the structure and function of retina in patients with DME,which was superior to using visual acuity solely to evaluate the retinal function in patients with DME.