Real-time studies of hypertension using non-mydriatic fundus photography and computer-assisted intravital microscopy

Abstract

Hypertension is asymptomatic until late stages of pathogenesis, rendering an effective means of detection for early diagnosis essential. The current method of diagnosing hypertension requires two or more sphygmomanometric readings over two or more office visits, which potentially hinders early detection. Though retinopathy is an indicator of vascular damage, it generally presents in later stages of hypertension. Previous and related studies have suggested that the microvasculature in the bulbar conjunctiva may be a sensitive site to assess vasculopathy. Conjunctival microangiopathy was assessed using CAIM and reported on a severity index (SI). Images of the retinal fundus were taken via non-mydriatic fundus photography and graded using the Scheie scale in the same subjects to compare with CAIM. Conjunctival microangiopathy was significantly elevated in hypertensive subjects (SI = 5.35 ± 1.04, n = 20) compared to control subjects (SI = 1.75 ± 1.39, n = 8; p ≤ 0.05), and correlated with time since disease diagnosis (R² = 0.33). Hypertensive subjects with Grade 1 retinopathy displayed increased conjunctival microangiopathy (SI = 5.85 ± 0.90, n = 13) compared to those without retinopathy (SI = 4.43 ± 0.53, n = 7; p ≤ 0.05). These data indicate a possible pre-retinopathy time window during which conjunctival microangiopathy may indicate the risk of organ damage, supporting the hypothesis that the conjunctival microcirculation may serve as a platform for early detection and monitoring disease progression.