Evaluation of corneal densitometry using Pentacam in patients with type 2 diabetes mellitus: a controlled cross-sectional study.

Purpose: This study aims to analyze corneal densitometry (CD) values in individuals diagnosed with Type 2 Diabetes Mellitus (DM) using the Pentacam Scheimpflug imaging system and to compare the obtained data with those from a control group consisting of healthy individuals.

Methods: The study included 74 eyes of 37 patients diagnosed with Type 2 Diabetes Mellitus (DM) and 54 eyes of 27 healthy volunteers matched for age and gender. All participants underwent measurements of flat keratometry (K1), steep keratometry (K2), maximum keratometry (Kmax), central corneal thickness (CCT), thinnest corneal thickness (TCT), average anterior and posterior elevation at the corneal apex (AAE and APE), corneal volume (CV) and CD. All measurements were performed using the Pentacam HR device (Oculus, Germany), which operates based on the Scheimpflug imaging principle. CD was evaluated in detail according to radial zones (0-2 mm, 2-6 mm, 6-10 mm, 10-12 mm) and corneal depths (anterior, central, posterior, and total). Only newly diagnosed Type 2 DM patients were included in the study, while those with diabetic retinopathy or maculopathy were excluded. HbA1c levels of all patients were recorded. Statistical analysis of the data was conducted using SPSS software version 22.0, and a p-value of < 0.05 was considered statistically significant.

Results: The mean age of the Type 2 Diabetes Mellitus (DM) group was 50.51 ± 8.93 years, while the mean age of the healthy control group was 50.89 ± 5.71 years. There were no statistically significant differences between the two groups in terms of age and gender distribution (p = 0.42 and p = 0.20, respectively). Similarly, no significant differences were observed between the groups in terms of K1, K2, Kmax, CCT, TCT, AAE,APE and CV (p = 0.51; p = 0.50; p = 0.48; p = 0.95; p = 0.99; p = 0.50; p = 0.29; p = 0,58 respectively). In contrast, CD values were significantly higher in the Type 2 DM group compared to the healthy control group across all zones (0-2 mm, 2-6 mm, 6-10 mm, 10-12 mm) and at all corneal depths (anterior, central, posterior, total) (p < 0.01). A low-level positive correlation was found between HbA1c levels and AAE (r = 0.281; p = 0.015). In addition, a very weak negative correlation was observed between HbA1c levels and CD values in the anterior 2-6 mm zone (r = -0.240; p = 0.035).

Conclusion: In this study, CD values were found to be significantly higher in patients with Type 2 DM compared to healthy individuals. This finding suggests that chronic hyperglycemia may lead to both morphological and functional changes in the corneal tissue.