Abstract
Aim: The aim of the study was to test possible correlation between corneal sub-basal nerve plexus changes and the grade of diabetic retinopathy (DR). Methods: A total of 38 patients with type 1 diabetes, divided into three groups according to the grade of diabetic retinopathy, and 12 age-matched healthy subjects underwent corneal confocal microscopy.
Corneal main nerve fiber density (CNFD), total corneal nerve fiber density (t-CNFD), nerve fiber length (CNFL) and nerve tortuosity (CNFT) were evaluated. Results: CNFD was lower in patients without DR, with mild grade DR, and with advanced grade DR than in healthy subjects (p < 0.0001, p = 0.004 and p < 0.0001, respectively).
There was also lower CNFD in patients with advanced grade DR than with mild grade DR (p = 0.036). T-CNFD was lower in patients without DR and advanced grade DR than in healthy subjects (p = 0.024 and p < 0.0001, respectively).
CNFL was lower in patients without DR and advanced grade DR than in healthy subjects (p = 0.028). CNFT was higher in patients with advanced grade DR than in healthy subjects and patients without DR (p < 0.0001; p = 0.001).
Conclusion: We demonstrated changes in corneal sub-basal nerve fiber count in all diabetic patient groups, with or without DR. The changes were more pronounced in patients without DR than with mild grade DR.
The study suggests no direct correlation between progression of corneal nerve fiber changes and changes in DR.