Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

• Published in: Scientific reports Vol. 10; no. 1; p. 11249
• Main Authors: Lin, Emily, Ke, Mengyuan, Tan, Bingyao, Yao, Xinwen, Wong, Damon, Ong, Lirong, Schmetterer, Leopold, Chua, Jacqueline
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 09.07.2020; Nature Publishing Group UK
• Subjects: Adult; Angiography; Capillaries; Capillaries - diagnostic imaging; Choroid - diagnostic imaging; Choroid - physiology; Circadian Rhythm; Diagnostic Imaging; Diurnal variations; Female; Fluorescein Angiography; Fundus Oculi; Healthy Volunteers; Humans; Macula Lutea - diagnostic imaging; Male; Medical imaging; Microvasculature; Middle Aged; Perfusion; Prospective Studies; Reproducibility of Results; Retina; Retinal Vessels - diagnostic imaging; Tomography; Tomography, Optical Coherence; Visual Acuity; Young Adult
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-68204-x

We evaluated the impact of diurnal variation on choroidal and retinal microvasculature and structural measurements using a swept-source optical coherence tomography angiography machine (SS-OCTA; PLEX Elite 9,000, Carl Zeiss Meditec, Inc., Dublin, USA). Fourteen participants who were without ocular diseases underwent SS-OCTA imaging using 3 × 3-mm macular scan pattern on two separate days at five time points. Choriocapillaris flow voids were generated to determine its density (percentage), size (μm) and numbers. Perfusion densities of the large superficial vessels, as well as capillaries on superficial and deep vascular plexuses were generated from retinal angiograms. Subfoveal choroidal and retinal thicknesses were manually measured. Repeated-measures ANOVA was used to investigate the impact of diurnal variation on choroidal and retinal measurements. There was no observable diurnal pattern for any of the flow void features, in terms of the density, size and numbers. There was a significant diurnal pattern observed in the choroidal thickness, where it decreased progressively during the day (P < 0.005). As opposed to sub-foveal choroidal thickness, there does not appear to be significant diurnal variation in choriocapillaris flow voids in normal individuals. This suggests that alterations of choriocapillaris flow deficit seen in pathological eyes will not be confounded by the diurnal fluctuation.