Background: Predominantly peripheral lesions (PPLs) could be any sign of diabetic retinopathy that only occurs outside the central 30° of the retina. These lesions represent an associated progression risk factor of retinopathy. Methods: An observational, cross-sectional, prospective, comparative study in subjects with (Group 1) or without (Group 2) diabetes was conducted. We determined the proportion and 95% confidence intervals of retinopathy level, the proportion of peripheral retinal changes, and the proportion of eyes with only PPLs of retinopathy. We compared peripheral retinal changes between subjects with and without diabetes by χ 2 test. Results: Two hundred subjects were evaluated, 77% female, mean age of 54.6 ± 7.35 years. In Group 1, 27% had some level of diabetic retinopathy and in 23%, it was bilateral. Only 2% of these subjects had PPLs. Peripheral retinal changes not associated to diabetes were found in 47% in Group 1 vs. 42% in Group 2 (p > 0.05). Conclusions: The conventional non-mydriatic camera for fundus eye photography is safe to evaluate subjects with diabetes and without ocular symptoms, in which cases peripheral retinal exploration could be omitted.

Vessel and perfusion densities may decrease before diabetic retinopathy appears; it is unknown whether these changes affect the contribution of vessel density to perfusion density. This was a non-experimental, comparative, prospective, cross-sectional study in non-diabetic subjects (group 1) and diabetics without retinopathy (group 2). Vessel and perfusion densities in the superficial capillary plexus were compared between groups at the center, inner, and full regions and by field (superior, temporal, inferior, nasal) using optical coherence tomography angiography. Coefficients of determination (R2) between vessel and perfusion densities were calculated to find the contribution of larger retinal vessels to perfusion density. Percent differences were used to evaluate the contribution of these vessels to perfusion density in a regression model. There were 62 participants, 31 eyes by group; vessel and perfusion densities as well as the coefficients of determination between them were lower in group 2, especially in the nasal field (R2 0.85 vs. 0.71), which showed a higher contribution of larger retinal vessels to perfusion density. The regression model adjusted to a quadratic equation. In diabetics without retinopathy the contribution of vessel density to perfusion density may decrease; a low vessel density may increase the contribution of larger retinal vessels to perfusion density.