The impact of flash intensity on retinal vessel oxygen saturation measurements using dual wavelength oximetry

Abstract

PURPOSE. To establish the optimal flash settings for retinal vessel oxygen saturation parameters using dual-wavelength imaging in a multiethnic group. METHODS. Twelve healthy young subjects (mean age 32 years [SD 7]; three Mediterranean, two South Asian, and seven Caucasian individuals) underwent retinal vessel oxygen saturation measurements using dual-wavelength oximetry, noncontact tonometry, and manual sphygmomanometry. In order to evaluate the impact of flash intensity, we obtained three images (fundus camera angle 30°, ONH centered) per flash setting. Flash settings of the fundus camera were increased in steps of 2 (initial setting of 6 and the final of 22), which reflect logarithmic increasing intensities from 13.5 to 214 Watt seconds (Ws). RESULTS. Flash settings below 27 Ws were too low to obtain saturation measurements, whereas flash settings of more than 214 Ws resulted in overexposed images. Retinal arteriolar and venular oxygen saturation was comparable at flash settings of 27 to 76 Ws (arterioles' range: 85%-92%; venules' range: 45%-53%). Higher flash settings lead to increased saturation measurements in both retinal arterioles (up to 110%) and venules (up to 92%), with a more pronounced increase in venules. CONCLUSIONS. Flash intensity has a significant impact on retinal vessel oxygen saturation measurements using dual-wavelength retinal oximetry. High flash intensities lead to supranormal oxygen saturation measurements with a magnified effect in retinal venules compared with arteries. In addition to even retinal illumination, the correct flash setting is of paramount importance for clinical acquisition of images in retinal oximetry. We recommend flash settings between 27 to 76 Ws. © 2013 The Association for Research in Vision and Ophthalmology, Inc.

Publication DOI: https://doi.org/10.1167/iovs.12-10493
Divisions: College of Health & Life Sciences > School of Optometry > Optometry
College of Health & Life Sciences > School of Optometry > Optometry & Vision Science Research Group (OVSRG)
College of Health & Life Sciences
College of Health & Life Sciences > School of Optometry > Vision, Hearing and Language
Additional Information: Copyright 2013 The Association for Research in Vision and Ophthalmology, Inc
Uncontrolled Keywords: dual wavelength,ethnicity,oximetry,photography,pigmentation,Ophthalmology,Sensory Systems,Cellular and Molecular Neuroscience
Publication ISSN: 1552-5783
Last Modified: 04 Jan 2024 08:07
Date Deposited: 05 Mar 2015 13:20
Full Text Link:
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
http://www.iovs ... ntent/54/4/2807 (Publisher URL)
PURE Output Type: Article
Published Date: 2013-04-17
Published Online Date: 2013-03-14
Authors: Heitmar, Rebekka (ORCID Profile 0000-0002-7657-1788)
Cubbidge, Robert P. (ORCID Profile 0000-0002-7851-1375)

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