Single retinal layer evaluation in patients with type 1 diabetes with no or early signs of diabetic retinopathy: The first hint of neurovascular crosstalk damage between neurons and capillaries?

Purpose: To analyze the retinal-choroidal changes in type 1 diabetes mellitus (DM1) patients with no or early signs of diabetic retinopathy (DR). Methods: Seventy-six eyes of 38 DM1 patients and 26 control eyes were included. Nine individual retinal layer thickness measurements were obtained using the spectral domain-optical coherence tomography automated segmentation algorithm. Results: The retinal nerve fiber layer was slightly thinner in all explored quadrants, even if the reduction was not significant in DM1 eyes versus control eyes. The inner nuclear layer (INL) thickness was thicker in all DM1 eyes versus control eyes in all quadrants (p < 0.050). Analyses adjusting for inner retinal thickness in all sectors confirmed INL thickening by about 4%, and also found a significant thinning of the ganglion cell layer (GCL) by about 3.5% in all DM1 subjects versus controls (p < 0.050). Conclusion: DM1 patients with no or early signs of DR present retinal changes particularly at the INL and GCL that might be correlated to initial findings of neurodegeneration.