Are circadian variations in the electroretinogram evident on routine testing?

Mira Marcus, Lorella Cabael, Michael F. Marmor

    Research output: Contribution to journalReview articlepeer-review

    7 Scopus citations


    We sought to determine whether routine ERGs using ISCEV standard stimuli, would show a pattern of circadian variation. We examined ERGs from 40 successive normal subjects who were tested at different times during regular laboratory operating hours of 9 am to 4 pm, and also reviewed high intensity a-waves from a subgroup. There were no obvious associations of either ERG amplitude or implicit time with time of day. No statistically significant difference was found between average ISCEV ERG parameters or high-intensity a-wave parameters obtained in the morning (9 am to 1 pm) and afternoon (1 pm to 4 pm). We conclude that time of day is not critical for routine ERG recordings, although small, variable, circadian changes may well be present. We suggest that the time of day be noted on clinical recordings, in case this information becomes relevant for a particular patient.

    Original languageEnglish
    Pages (from-to)165-169
    Number of pages5
    JournalDocumenta Ophthalmologica
    Issue number2
    StatePublished - 1 Mar 2004


    • Circadian variation
    • Electroretinogram
    • Photoreceptors
    • Retinitis pigmentosa

    ASJC Scopus subject areas

    • Ophthalmology
    • Sensory Systems
    • Physiology (medical)

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