Glucose Dispersion Is Associated With Contrast Sensitivity Beyond Average Glycemia

Background: HbA1c and mean glucose summarize average glycemia but do not capture glucose dispersion. Whether free-living glucose dispersion is associated with visual function beyond average glycemia remains unclear. Aim: To determine whether glucose dispersion is associated with mesopic and photopic contrast sensitivity independently of HbA1c and contemporaneous CGM mean glucose. Methods: We analyzed 2,218 AI-READI participants with continuous glucose monitoring and visual-function data. Glucose dispersion was represented primarily by mean absolute deviation from mean glucose (AAD), and associations were assessed using multivariable linear regression. Results: Higher AAD was associated with lower mesopic and photopic contrast sensitivity after adjustment for age and HbA1c (beta = -0.188 and -0.165; P = 1.28e-11 and 8.55e-9) and after adjustment for age and CGM mean glucose (beta = -0.221 and -0.195; P = 4.84e-13 and 5.66e-10). Associations persisted with additional adjustment and sensitivity analyses; glucose SD yielded concordant results. Conclusion: Glucose dispersion is associated with contrast sensitivity beyond average glycemia, suggesting that glycemic exposure may relate to visual function through its average level and dispersion.