Rod Electroretinograms Elicited by Silent Substitution Stimuli from the Light-Adapted Human Eye.

YesThe purpose of this paper is to demonstrate: 1) that silent substitution stimuli can be used generate electro-retinograms (ERGs) that effectively isolate rod photoreceptor function in humans without the need for dark adaptation and 2) that this approach constitutes a viable alternative to current clinical standard testing protocols. Rod-isolating and non-isolating sinusoidal flicker stimuli were generated on a 4 primary LED ganzfeld stimulator to elicit ERGs from non-dark adapted participants with normal and compromised rod function. Responses were subjected to Fourier analysis and the amplitude and phase of the fundamental were used to examine temporal frequency and retinal illuminance response characteristics. ERGs elicited by rod isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30Hz. Responses are optimal between 5 – 8 Hz and between 10-100 photopic Td. There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. Analysis of signal to noise ratios reveals significant differences between subjects with normal and compromised rod function. Silent substitution provides an effective method for the isolation of human rod photoreceptor function in subjects with normal as well as compromised rod function when stimuli are used within appropriate parameter ranges. Translational Relevance: This method of generating rod ERGs rod isolation can be achieved without time consuming periods of dark adaptation and provides improved isolation of rod- from cone-based activity and will lead to the development of faster clinical electro-physiological testing protocols with improved selectivity