Human electroretinal responses to grating patterns and defocus changes by global flash multifocal electroretinogram

PLoS One. 2015 Apr 13;10(4):e0123480. doi: 10.1371/journal.pone.0123480. eCollection 2015.


The electrical response of the retina was examined as a function of retinal region, using stimuli of various spatial frequencies in the first experiment. In the second experiment, the regional response of the retina to defocus at high and low spatial frequencies was investigated. Twenty three subjects were recruited for global flash multifocal electroretinogram (mfERG) in experiment 1. Black and white gratings (printed on plastic transparent sheets) of four spatial frequencies (SF), 0.24, 1.2, 2.4 and 4.8 cycle per degree were presented in front of the mfERG stimulation. The amplitudes and implicit times of the direct (DC) and induced (IC) components of mfERG responses were pooled into six concentric rings for analysis. There was low amplitude DC at low SF, which increased with increasing SF, and which decreased with increasing eccentricity. The IC was high in amplitude at all SF and reduced in amplitude with increasing eccentricity. Our findings suggested that outer and inner retina had different characteristics in processing spatial details. In experiment 2, Twenty-three young adults were recruited for mfERG measurement. The retinal electrical responses for low (0.24cpd) and high (4.8cpd) SF under fully corrected conditions of short-term negative defocus (-2D) and short term positive defocus (+2D) conditions were measured. There was a sign-dependent response to defocus in the DC response, mainly in peripheral regions. The sign dependent response at low SF was more obvious than that at high SF, and was located more peripherally. The IC response showed no clear trends for either defocus condition. The human retina seems to have a decoding system for optical defocus, which was tuned for low spatial frequency, and was located in the retinal near periphery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Electroretinography / methods*
  • Evoked Potentials, Visual
  • Humans
  • Intraocular Pressure
  • Myopia / pathology
  • Photic Stimulation
  • Refractive Errors
  • Reproducibility of Results
  • Retina / pathology*
  • Signal Processing, Computer-Assisted
  • Young Adult

Grant support

This study was supported by the General Research Fund (PolyU 5605/13M) from The Research Grants Committee of the Hong Kong SAR and the associated fund (Research Postgraduate) from The Hong Kong Polytechnic University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.