Glucose metabolism status is associated with changes in macular thickness

Design: Cross-sectional population-based cohort study. Purpose: Macular thinning may be an early sign of diabetic retinopathy. We therefore evaluated to what extent macular thickness differed between individuals with prediabetes (preDM2) and individuals with type 2 diabetes (DM2) without cysts compared with individuals with a normal glucose metabolism (NGM). Methods: Using SD-OCT we measured macular thickness in five ETDRS subfields in 2385 participants (mean age 59 ± 8 years, 50% men, 1397 NGM, 357 preDM2, 631 DM2). Results: After adjustment for age, sex, and spherical equivalent, individuals with preDM2 showed a significant decrease in pericentral superior macular thickness compared with individuals with NGM (-3.34 ± 1.28 µm, P<0.01). In individuals with DM2 without cysts, the four pericentral quadrants were significantly thinner compared with individuals with NGM (range: -5.42 ± 1.04 µm to -5.91 ± 1.03 µm, P<0.001). There was a significant linear trend of pericentral macular thinning with severity of glucose metabolism status (P<0.001). Conclusions: This study demonstrates that the pericentral macular thickness decreases with worsening of glucose metabolism. This may reflect early neurodegenerative changes.