Orthogonal Polarization Spectral Imaging of the Conjunctival Microcirculation in Diabetes Mellitus

Abstract

Abstract: : Purpose: Microvascular abnormalities are a hallmark of diabetic retinopathy, potentially causing loss of vision and blindness. Orthogonal Polarization Spectral (OPS) Imaging is a new clinical technique that uses polarized light to visualize the microcirculation of organ surfaces. We used this technique to compare the conjunctival microvasculature in diabetic and age-matched nondiabetic persons in order to establish a diagnostic index of microvascular changes in diabetes mellitus. Methods: For this purpose, the eyes of 15 diabetic patients and 15 nondiabetic controls were investigated. The experiments were performed on the inferior and nasal part of the bulbar conjunctiva of each eye. The images were computer analyzed and several parameters were measured. In addition, a qualitative characterization of the conjunctival microvasculature was performed. Results: In diabetic patients, a lower percentage of conjunctival microvessels was measured than in controls. Furthermore, a significant increase in diffusion distance was revealed in the diabetic population. Microvascular abnormalities, such as capillary elongation, sludging, vessel distension and vessel tortuosity were more frequently present in the diabetic group, as compared to the controls. Other frequently seen abnormalities in diabetic patients were beaded vessels, box car blood flow phenomenon, hemosiderin deposits and blocked vessels. Conclusions: OPS imaging was found to be a reliable technique to visualize the conjunctival microcirculation and to measure systemic microvascular parameters. Microcirculation of diabetic patients exhibited significant differences in relation to the controls, in particular decreased vascularity. OPS imaging is an easy to handle diagnostic device with interesting opportunities in diagnosis of microvascular conjunctival and systemic disorders.

Keywords: diabetes • imaging/image analysis: clinical • conjunctiva