Purpose
To measure retinal blood vessel diameters in hypertensive patients using spectral domain optical coherence tomography (SD-OCT).
Methods
A cohort of 47 hypertensive patients (94 eyes) underwent an SD-OCT exam (Spectralis, Heidelberg Engineering, Heidelberg, Germany). Two cubes of seven high-resolution horizontal scans each were placed at the superior and inferior borders of the disc to include the large temporal retinal vessels (Figure 1). Inter-scan interval was 240 µm. The outer diameter of the main temporal arteriole and venule was measured manually (Image J software, National Institute of Health, USA) at distances 480 µm, 720 µm, 960 µm, 1200 µm and 1440 µm from the optic disc border, superiorly and inferiorly (Figure 2). Previously reported results from 29 healthy subjects (58 eyes) were used as controls.
Results
The mean ± SD age of the hypertensive patients was 57.3 ± 8.85 years. Their mean ± SD systolic and diastolic blood pressures were 140.23 ± 13.22 mmHg and 82.17 ± 10.68 mmHg, respectively. The mean ± SD diameters of the arterioles and venules in the hypertensive cohort steadily decreased from 130.85 ± 13.7 µm and 162.02 ± 16.04 µm at 480 µm from the optic disc to 119.7 ± 13.45 µm and 151.35 ± 15.44 µm at 1440 µm from the optic disc, respectively. The overall mean artery-to-vein ratio (AVR) in hypertension was 0.81. Uncontrolled hypertensive patients had narrower mean arteriolar diameters compared to controlled hypertensive patients at all points of measurement, reaching statistical significance in the superior arterioles (P = 0.009). Compared to healthy controls, mean arteriolar diameters and mean AVR were smaller (P < 0.04), whereas mean venular diameters were larger (P < 0.01) at all points of measurement in hypertensive patients.
Conclusions
Measurement of large temporal retinal vessel diameters by SD-OCT may be used as an adjunctive tool for the assessment of hypertension.