The Association among Corneal Nerve Metrics, Ocular Surface Integrity, and Renal Function in Type 2 Diabetes.

Purpose: To investigate the association among corneal nerves, ocular surface, and renal function in diabetes, and to compare these variables in patients with and without chronic diabetic kidney disease (DKD). Design: Cross-sectional study. Participants: This study included 538 patients with type 2 diabetes. Methods: All subjects received renal function tests, in vivo confocal microscopy examinations for corneal nerves, epithelial and immune cells, as well as ocular surface subjective and objective assessments. Univariable and multivariable regression analyses were used to determine the relationship between corneal nerve variables and renal function parameters. Multivariable logistic regression was performed to examine factors that were associated with DKD. Main Outcome Measures: The association between corneal nerve metrics and renal function parameters. Results: After adjusting for potential confounders, lower corneal nerve fiber density (CNFD) was significantly associated with higher urine albumin (P = 0.019), and higher corneal nerve fiber width was significantly associated with higher urine albumin and higher urine albumin-creatinine ratio (P < 0.001 and P = 0.001, respectively). Corneal nerve fiber length and width were significantly associated with DKD (P = 0.028 and P = 0.025, respectively). Compared with the non-DKD group, patients with DKD had significantly lower CNFD, length, area, and fractal dimension, as well as increased width, decreased epithelial cell density and count, and larger epithelial cell size (all P < 0.05). Patients with DKD presented with significantly lower Schirmer value and tear break-up time, and increased corneal staining and Ocular Surface Disease Index score than non-DKD patients (all P < 0.05). Conclusions: In diabetes, the impairment of corneal nerves is associated with the deterioration of renal function. Patients who have poor corneal nerve status are at risk of DKD, and patients who have DKD should be examined for corneal neuropathy. Financial Disclosures: The author has no/the authors have no proprietary or commercial interest in any materials discussed in this article.