Eline E. B. De Clerck; Jan S. A. G. Schouten; Tos T. J. M. Berendschot; Henny J. M. Beckers; Nicolaas C. Schaper; Miranda T. Schram; Coen D. A. Stehouwer; Carroll A. B. Webers
Purpose: The purpose of this study was to assess thinning of the peripapillary retinal nerve fiber layer (RNFL) in prediabetes or type 2 diabetes without diabetic retinopathy (DM2 w/o DRP) compared with that in individuals with normal glucose metabolism (NGM).
Methods: We measured sectoral and mean RNFL thickness in a 3.45-mm-diameter circular scan centered on the optic nerve head, using spectral domain optical coherence tomography in 1172 participants from The Maastricht Study (a population-based cohort of individuals 59 ± 8 years of age, 47% men, 699 NGM, 186 with prediabetes, and 287 with DM2 w/o DRP). Multivariate linear regression was used to assess the association between RNFL thickness and glucose metabolism status, adjusted for age and sex.
Results: In individuals with prediabetes, the temporal RNFL was thinner than that in individuals with NGM after adjustment (β = −2.28 μm [95% confidence interval [CI], −4.44 to −0.13], P = 0.04), whereas in individuals with DM2 w/o DRP, the temporal inferior (β = −3.66 μm [95% CI, −6.46 to −0.85], P = 0.01), the temporal superior (β = −2.99 μm [95% CI, −5.95 to −0.02], P = 0.05), the temporal (β = −2.73 μm [95% CI, −4.62 to −0.84], P < 0.01), and the mean RNFL (β = −1.88 μm [95% CI, −3.51 to −0.26], P = 0.02) were thinner than those in individuals with NGM.
Conclusions: Temporal RNFL thinning is already present in individuals with prediabetes. More widespread RNFL thinning occurs in individuals with DM2 w/o DRP, that is before vascular changes are detected. This suggests preferential retinal nerve fiber layer loss in areas related to the papillomacular bundle.