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Abstract
PURPOSE: To assess the relationship of foveal microcirculation to contrast sensitivity function in early diabetes mellitus. METHODS: Twenty patients with diabetes with visual acuity of 20/25 or better without clinically significant macular edema were evaluated. Measurements of contrast sensitivity at four spatial frequencies (3, 6, 12, and 18 cycles/degree [c/deg]), macular capillary blood velocity (CBV), capillary density (PIA: perifoveal intercapillary area), foveal avascular zone (FAZ), and microaneurysm count were performed. Contrast sensitivity data collected from age-matched normal subjects and previously published normal angiographic data were used for comparison with our cohort with diabetes. RESULTS: The CBV was significantly reduced (P < 0.0001) and PIA and FAZ were significantly enlarged (P < 0.0001) when compared with healthy subjects. Contrast sensitivity was significantly lower in the group with diabetes at 6 (P = 0.01) and 12 (P = 0.002) c/deg as compared with healthy control values. FAZ and PIA correlated significantly (FAZ; r = -0.60, P = 0.005; PIA; r = -0.54, P = 0.02) with contrast sensitivity at 12 c/deg. CONCLUSIONS: The alterations of the perifoveal network are related to selective disturbances of central visual function as measured by contrast sensitivity. In patients with diabetes measurement of contrast sensitivity may provide a clinical adjunct in further identifying early ischemic diabetic maculopathy.