Diabetes induces changes in neuroretina before retinal vessels: a spectral-domain optical coherence tomography study
AIM A comparison of retinal thickness (RT) measurements with optical coherence tomography (OCT) in patients with type 1 diabetes mellitus (DM) and no or minimal diabetic retinopathy (DR) versus healthy controls. METHODS Fifty-three patients with type 1 DM with no or minimal DR underwent full ophthalmic examination, fundus photography and OCT. Mean RT measured by OCT was calculated for the central fovea, the fovea, the pericentral and the peripheral area of the macula, and compared to healthy controls. RESULTS Mean RT in the pericentral area was lower in patients with minimal DR (267 microm +/- 20 microm; n = 23) compared to healthy controls (281 microm +/-13 microm; p = 0.005; n = 28). Mean pericentral RT in patients without DR (276 microm +/-14 microm; n = 30) was less than pericentral RT in healthy controls, but higher than in patients with minimal DR, without being statistically significant. None of the other regions showed a significant change. CONCLUSION In this study a significantly decreased pericentral RT was measured in patients with minimal DR compared to healthy controls. This could be explained by a loss of intraretinal neural tissue in the earliest stage of DR.