Corneal thickness differences between type 2 diabetes and non-diabetes subjects during preoperative laser surgery examination

Aims: To evaluate the differences in corneal thickness between type 2 diabetes subjects with HbA1c under 7.0% and non-diabetes subjects during their preoperative laser surgery examinations. Methods: The mean of five consecutive corneal thickness measurements at the central and mid-peripheral cornea was obtained by means of noncontact scanning-slit comeal topography (Orbscan Topography System II; Orbscan, Inc., Salt Lake City, UT, USA) in 35 myopic non-insulin dependent type 2 diabetes subjects (17 males and 18 females) and 48 healthy myopic controls (23 males and 25 females). Results: The corneal thickness values at the central and mid-peripheral cornea were significantly higher in the diabetic group (p < .001). The diabetic subjects presented the highest thickness value in the superior cornea (n = 22; 62.9%) followed by the nasal (n = 9; 25.7%) and the temporal (n = 4; 11.4%) cornea, but never in the inferior cornea. The control subjects presented the highest thickness value in the superior cornea (n = 19; 39.6%) followed by the nasal (n = 18; 37.5%), the inferior (n = 6; 12.5%), and the temporal (n = 3; 6.3%) cornea. The central corneal thickness (CCT) of the diabetes patients was not statistically correlated with their HbA1c (r(2) = .078; p = .104), body-mass index (r(2) = .007; p = .633), and time from diagnosis of diabetes (r(2) = .025; p = .363), but it was correlated with their corneal endothelial cell density values (r(2) = .543; p < .001). Conclusions: Diabetes subjects with HbA1c under 7.0% who are candidates for laser refractive surgery present thicker corneas than their age-matched control subjects. In these patients, there is a correlation between their CCT values and their corneal endothelial cell density values, so when higher CCT values were found, lower corneal endothelial cell density values were observed. (C) 2017 Elsevier Inc. All rights reserved.