Evaluating diurnal variations in retinal perfusion using optical coherence tomography angiography

Area of Science:

• Ophthalmology
• Medical Imaging
• Physiology

Background:

• Optical coherence tomography angiography (OCTA) is a key non-invasive imaging technique for assessing retinal and choroidal vasculature.
• Choroidal perfusion exhibits diurnal variations, typically lower in the morning and higher in the afternoon.
• Retinal perfusion is primarily regulated by intrinsic autoregulatory mechanisms.

Purpose of the Study:

• To investigate diurnal changes in retinal perfusion using OCTA in healthy adult eyes.
• To identify potential factors influencing retinal perfusion, such as mean arterial pressure (MAP) and intraocular pressure (IOP).

Main Methods:

• Prospective study involving healthy volunteers.
• Repeated measurements of MAP, IOP, macular volume (MV), subfoveal choroidal thickness (SFCT), foveal avascular zone (FAZ), and retinal perfusion (SCP, DCP, FR) at 7 a.m. and 4 p.m.
• Evaluation of MAP and IOP influence on retinal perfusion.

Main Results:

• Significant diurnal changes observed in MAP and SFCT.
• No significant diurnal fluctuations detected in retinal perfusion (SCP, DCP, FR), FAZ size, or MV.
• No significant correlation found between MAP or IOP and retinal perfusion parameters.

Conclusions:

• OCTA analysis in healthy adults shows consistent retinal perfusion throughout the day.
• Retinal blood flow appears independent of diurnal MAP fluctuations.
• Findings support the role of autoregulation in maintaining stable retinal perfusion.