Abstract
Purpose :
OCT-angiography (OCT-A) is used to visualize peripapillary retinal microcirculation in optic disc disorders. As microcirculation is affected by several internal and external factors, it was the purpose of this study to investigate a potential circadian rhythm of peripapillary vessel density (VD) during office hours in healthy eyes. APS based analysis (1) may have the advantage to normalize VD analysis on a fixed anatomical BMO-center-fovea axis and thus compensate for head tilt.
Methods :
Thirty-five eyes of 35 healthy (28±11.0y; 22f, 13m) subjects were recruited at the Department of Ophthalmology, University of Erlangen. All subjects underwent en face OCT-A (Spectralis OCT II, Heidelberg Engineering, Germany) at three different daytimes: 9h am, 3h pm and 9h pm data were analyzed with the Erlangen Angio-Tool (EA-Tool), which allows BMO- and APS-based analysis (APS-ify). Overall and sectorial BMO-based, APS-ified peripapillary VD was calculated. For the analysis a linear mixed model with type III sum of squares was employed with the daytime and sector as predictor variables to examine the differences in the vessel density.
Results :
Overall mean peripapillary VD was 42.12±5.9. Mean peripapillary VD was 41.5±6.15 (9 a.m.), 43.19±5.69 (3h pm)., and 41.66±6.69 (9h pm). Peripapillary VD differed significantly between 9h am and 3h pm (p=0.0001), and 3h pm and 9h pm (p=0.0006), respectively. No difference was observed between peripapillary VD at 9h am compared to 9h pm (p>0.05). Regional analysis showed a significant difference of VD in temporal regions (sector 4) (p=0.0059 compared to sector 2; p<0.0001 for sector 1 and 3), contrary to the other sectors (p>0.05).
Conclusions :
Timepoint of OCT-A examination between 9h a.m. and 9h p.m. had a significant impact on BMO-based APS-ified peripapillary VD in healthy eyes.
(1) Mardin CY, Schottenhamml J, Dehcordi SF, Mueller M, Maier AK, Hohberger B. ‘APSifyed’Bruch’s membrane opening (BMO) based peripapillary OCT-A analysis. Investigative Ophthalmology & Visual Science. 2021 Jun 21;62(8):3369.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.