Mean Arteriolar Diameter Measured from Wide-Field Swept-Source OCT Angiography: A Highly Sensitive Indicator for Mean...

To investigate the metrics of retinal arterioles and venules based on the en face images of the superficial retina using wide-field swept-source OCT angiography (SSOCTA) and assess their relationships with specific systemic parameters in a normal sample.

Cross-sectional study.

Normal volunteers with no history of hypertension, diabetes, or significant eye diseases were recruited at the outpatient clinic of the First Affiliated Hospital of Xi'an Jiaotong University. Eligible eyes had a corrected visual acuity of 20/25 or better and an intraocular pressure (IOP) not exceeding 21 mmHg.

The SSOCTA scans of 24 × 20 mm in size were acquired from both eyes of each participant, along with measurements of axial length (AL), IOP, real-time mean arterial pressure (MAP), and body mass index (BMI). Retinal arterioles and venules were manually segmented and distinguished from the disc margin to their capillary junctions in the superficial retinal layer. Image processing and calculations were performed using ImageJ.

The averaged caliber and fractal dimension of arteries and veins, as well as the arteriovenous ratio, were calculated from binarized vascular images. Generalized linear mixed models were used to test correlations between systemic parameters and these metrics.

A total of 54 eyes from 44 participants were included after screening. Univariate analysis revealed a significant negative impact of MAP on averaged caliber of retinal artery (B = -0.003, P = 0.004) and averaged caliber of retinal vein (ACvein) (B = -0.002, P = 0.045), whereas age, sex, BMI, AL, and IOP showed no significant impact on these metrics. Variations among graders significantly influenced most metrics; however, real-time MAP continued to predict retinal arteriolar caliber after adjusting for graders (B = -0.002, P = 0.03).

The mean arteriolar diameter measured using wide-field SSOCTA could serve as a highly sensitive indicator of systemic vascular changes.

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