Purchase this article with an account.
M.R. Marcus, L. Cabael, M.F. Marmor; Effects of Circadian Rhythm on ERG Testing Results in a Clinical Setting . Invest. Ophthalmol. Vis. Sci. 2003;44(13):4874.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Modest diurnal variations have been reported to occur in the clinical electroretinogram (ERG). This study evaluated whether these diurnal variations are a significant influence on ERG recordings from normal subjects in a clinical setting. Methods: We reviewed the charts of 40 normal subjects between the ages 15-40, for whom the time of testing was recorded. Twenty-one people had been tested during the morning, 9:00 to 12:55. Nineteen people had been tested between 13:00 and 16:00. Standard ISCEV ERG responses were plotted against the time of day; and mean and median values were compared between the morning and the afternoon times. Results: There were no statistically significant changes in ERG amplitudes or implicit time during the course of the day (9:00 to 16:00) for either scotopic or photopic ISCEV standard ERG parameters (amplitudes and implicit times). However, small variations may have been hidden within the spread of normal results Conclusions:The literature reports that scotopic responses from normal subjects are lower for a brief period after the onset of morning light, but we found no significant diurnal changes during regular hours of operation in a clinical setting. Nevertheless, small diurnal changes may have been masked, and diurnal effects could be different in disease. Our results suggest that ERG recordings for most purposes can be done without concern over time of day, but time should be noted in the record so that the information is available if needed for a special case or for critical sequential recordings.
This PDF is available to Subscribers Only