Comparison of the uniform-field electroretinogram and the pattern electroretinogram to checkerboard and bar gratings

Abstract

Purpose: To compare the electroretinal response associated with the uniform-field electroretinogram (UF-ERG) to that of the pattern electroretinogram (PERG) to checkerboard and bar-grating stimuli.

Methods: UF-ERG and PERG to bars and checkerboard were recorded for 18 visually normal subjects (36 eyes) of mean age 45 years (range 20-75). UF-ERG was recorded to the increment and decrement of a 200-ms duration luminance modulation. Luminance onset and offset UF-ERG responses were averaged to produce a simulation of the PERG response. The mean amplitude and implicit time for the P₅₀ and N₉₅ potentials of actual and simulated PERG responses were recorded for each eye in the cohort.

Results: The simulated PERG waveform resulting from arithmetic averaging of the UF-ERG to luminance increment and decrement was characterized by prominent positive and negative components resembling those of the P₅₀ and N₉₅ PERG potentials. Implicit timing of the P₅₀ potential was lengthened in the actual PERG to bars and checks relative to that of the simulation (P < 0.05, P < 0.001). Amplitude of the N95 potential was greater in the PERG to bars than in the PERG to checks (P < 0.05) or the simulated PERG (P < 0.001). The amplitude and implicit timing of all waveform components were significantly correlated between the actual and simulated PERG.

Conclusions: The UF-ERG to light onset and offset can be reliably recorded in human subjects. The extent to which the simulated PERG recapitulates the actual PERG response is better with checkerboard rather than bar-grating stimuli.

Keywords: Pattern electroretinogram; Photopic negative response; Uniform-field electroretinogram.