July 2019
Volume 60, Issue 9
Free
ARVO Annual Meeting Abstract  |   July 2019
The incidence of negative electroretinograms in a healthy adult cohort
Author Affiliations & Notes
  • Talib Dar
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
  • Isabelle Chow
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
  • Xiaofan Jiang
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
  • Taha Bhatti
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
  • Ambreen Tariq
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
  • Katie Williams
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
    Twin Research and Genetic Epidemiology, King’s College London, St Thomas’ Hospital Campus, London, United Kingdom
  • Pirro G Hysi
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
    Twin Research and Genetic Epidemiology, King’s College London, St Thomas’ Hospital Campus, London, United Kingdom
  • Christopher J Hammond
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
    Twin Research and Genetic Epidemiology, King’s College London, St Thomas’ Hospital Campus, London, United Kingdom
  • Omar Abdul Rahman Mahroo
    UCL Institute of Ophthalmology, Bath Street, University College London, London, United Kingdom
    Ophthalmology, King's College London, St Thomas' Hospital Campus, London, United Kingdom
  • Footnotes
    Commercial Relationships   Talib Dar, None; Isabelle Chow, None; Xiaofan Jiang, None; Taha Bhatti, None; Ambreen Tariq, None; Katie Williams, None; Pirro Hysi, None; Christopher Hammond, None; Omar Mahroo, None
  • Footnotes
    Support  Wellcome Trust Grant 206619/Z/17/Z; NIHR Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology; Fight for Sight UK
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 2497. doi:
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      Talib Dar, Isabelle Chow, Xiaofan Jiang, Taha Bhatti, Ambreen Tariq, Katie Williams, Pirro G Hysi, Christopher J Hammond, Omar Abdul Rahman Mahroo; The incidence of negative electroretinograms in a healthy adult cohort. Invest. Ophthalmol. Vis. Sci. 2019;60(9):2497.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : A negative dark-adapted electroretinogram (ERG) waveform is diagnostically significant. Occasionally, it can be an unexpected finding, raising the question as to whether a small proportion of healthy adults might produce negative ERGs. We investigated the incidence of electronegative responses to standard dark-adapted stimuli in a cohort of largely healthy adult volunteers.

Methods : ERG waveforms obtained as part of a previous prospective study investigating heritability of retinal response parameters were analysed. Participants were 211 volunteers recruited from the TwinsUK cohort, who underwent ERG testing according to international standard protocols. Pupils were pharmacologically dilated. Responses were recorded using a conductive fibre electrode placed in the lower conjunctival fornix. Participants underwent 20 min dark adaptation prior to delivery of standard scotopic stimuli. A-wave and b-wave amplitudes were extracted for each subject from dark-adapted responses to 3.0 cd m-2 s (“standard”) and 10.0 cd m-2 s (“brighter”) white flashes. The b:a ratio was calculated. Proportions of responses with b:a ratios less than 1 were noted.

Results : Recordings from both eyes of all participants were included. Mean (SD) age was 62.4 (11.4) years. 93% were female. Mean (SD) b:a ratios for right and left eyes respectively were 1.86 (0.33) and 1.81 (0.29) for the standard flash, and 1.62 (0.25) and 1.58 (0.23) for the brighter flash. The average b:ratio was lower for the brighter flash (p<0.0001). Minimum ratios were 1.12 and 1.13 for the standard flash, and 1.15 and 1.05 for the brighter flash, for right and left eyes respectively. No waveforms were electronegative.

Conclusions : Of 422 largely healthy eyes, no waveforms were electronegative. The findings support the notion that electronegative waveforms (in response to the standard flash strengths and in the recording conditions of the present study) are abnormal, and should prompt further investigation.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

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