Evaluating diurnal changes in choroidal sublayer perfusion using optical coherence tomography angiography

PURPOSE: To investigate diurnal changes of choroidal sublayer perfusion in normal eyes and to identify influencing factors using optical coherence tomography angiography (OCTA). METHODS: A prospective study was conducted on healthy volunteers, each of whom underwent repeated measurements of subfoveal choroidal thickness (SFCT) via enhanced depth imaging (EDI) optical coherence tomography (OCT) as well as perfusion of choroidal vascular sublayers using OCTA at 7 a.m., 12 p.m., 4 p.m. and 8 p.m. Possible interactions between diurnal variations and other factors, such as mean arterial pressure (MAP), gender and age, were evaluated. RESULTS: A total of 22 eyes from 22 participants were analysed. Mean age of participants was 56 years. A significant pattern of diurnal variation was observed for SFCT (p /=60 years) had fewer diurnal changes (p = 0.042). CONCLUSION: Optical coherence tomography angiography-based analysis of choroidal sublayer perfusion demonstrated significant diurnal variations. Therefore, it is important to account for time of day, when comparing longitudinal OCTA data.