R Hamilton1,2, K Graham3,4. 1. Department of Clinical Physics and Bio-engineering, NHS Greater Glasgow and Clyde, Glasgow, UK. ruth.hamilton@glasgow.ac.uk. 2. College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK. ruth.hamilton@glasgow.ac.uk. 3. Department of Clinical Physics and Bio-engineering, NHS Greater Glasgow and Clyde, Glasgow, UK. 4. College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
Abstract
PURPOSE: To quantify dark-adapted (DA) skin ERG changes during 20 min of dark adaptation. METHODS: Sixteen healthy adult subjects were dark-adapted for 20 min during which ISCEV standard dim (0.01 phot cd s m(-2)) white flash ERGs were recorded at 1, 2, 3, 4, 5, 10, 15 and 20 min, and bright (3 phot cd s m(-2)) white ERGs were recorded at 2, 5, 10, 15 and 20 min without mydriasis and using skin electrodes. Amplitudes and peak times were normalised to 20 min values. RESULTS: Halving dark adaptation from 20 to 10 min had no measureable effect on the DA 3 ERG and caused a 10 % amplitude loss (range 0-23 %) only for the DA 0.01 ERG b-wave amplitude. No significant peak time changes resulted, nor increased parameter variability. CONCLUSION: Reducing dark adaptation from 20 to 10 min or even less has an effect on only DA 0.01 ERGs. Shorter dark adaptation than 20 min may not compromise the clinical utility of the ERG providing clinics adhere to the usual standards of adequate reference data.
PURPOSE: To quantify dark-adapted (DA) skin ERG changes during 20 min of dark adaptation. METHODS: Sixteen healthy adult subjects were dark-adapted for 20 min during which ISCEV standard dim (0.01 phot cd s m(-2)) white flash ERGs were recorded at 1, 2, 3, 4, 5, 10, 15 and 20 min, and bright (3 phot cd s m(-2)) white ERGs were recorded at 2, 5, 10, 15 and 20 min without mydriasis and using skin electrodes. Amplitudes and peak times were normalised to 20 min values. RESULTS: Halving dark adaptation from 20 to 10 min had no measureable effect on the DA 3 ERG and caused a 10 % amplitude loss (range 0-23 %) only for the DA 0.01 ERG b-wave amplitude. No significant peak time changes resulted, nor increased parameter variability. CONCLUSION: Reducing dark adaptation from 20 to 10 min or even less has an effect on only DA 0.01 ERGs. Shorter dark adaptation than 20 min may not compromise the clinical utility of the ERG providing clinics adhere to the usual standards of adequate reference data.
Entities:
Keywords:
Dark adaptation; Dark-adapted ERG; ISCEV standard
Authors: Magella M Neveu; Alan Dangour; Elizabeth Allen; Anthony G Robson; Alan C Bird; Ricardo Uauy; Graham E Holder Journal: Doc Ophthalmol Date: 2011-08-04 Impact factor: 2.379