title: Multifocal Electroretinogram in Diabetic Macular Edema; Correlation with Visual Acuity and Optical Coherence Tomography.
abstract: OBJECTIVE
  To evaluate multifocal electroretinogram (mfERG) changes in eyes with diabetic macular edema (DME) and investigate any possible correlation with optical coherence tomography (OCT) features and visual acuity (VA).
  
  
  METHODS
  Twenty-nine right eyes of 29 subjects with DME due to non-proliferative diabetic retinopathy and 30 eyes of 30 normal subjects were evaluated. All patients underwent a complete ophthalmic examination. Sixty-one scaled hexagon mfERG responses were recorded. Components of the first order kernel of N1, N2, and P1 in five concentric rings centered on the fovea, were measured in both groups. Correlation and regression analyses were performed among VA, central macular thickness (CMT) based on OCT, mfERG amplitude, and latency of the N1, N2 and P1 waves.
  
  
  RESULTS
  Significant differences were observed in all mfERG parameters in five-ring regions of the retina between eyes with DME versus controls (P < 0.05). There were significant correlations among VA with N2 (P = 0,001, b = 0.73) and P1 amplitudes (P = 0.001, b = -0.84) in the central macular area, and there was a borderline association between VA and CMT (P = 0.042, b = 0.392).
  
  
  CONCLUSIONS
  Amplitudes of mfERG components (N1, P1, and N2) are significantly reduced and their latencies are delayed in eyes with DME indicating functional impairment in the outer retina. The mfERG total amplitude was significantly correlated with VA even more than CMT, therefore the combined use of OCT and mfERG for macular evaluation may better evaluate visual status in DME patients.
authors.affiliation: Department of Optometry, Faculty of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Neda Mazahery
authors.initials: NM
authors.lastname: Tehrani
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Riazi-Esfahani
authors.affiliation: Department of Optometry, Faculty of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Jafarzadehpur
authors.affiliation: Department of Optometry, Faculty of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Mirzajani
authors.affiliation: Department of Audiology, School of Rehabilitation Sciences, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Talebi
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Abdulrahim
authors.initials: A
authors.lastname: Amini
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mazloumi
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Ramak
authors.initials: R
authors.lastname: Roohipoor
authors.affiliation: Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Riazi-Esfahani
keywords: Diabetes Mellitus; Diabetic Macular Edema; Multi-focal Electroretinography; Optical Coherence Tomography; Visual Acuity