Scheimpflug Camera and Swept-Source Optical Coherence Tomography in Pachymetry Evaluation of Diabetic Patients

The comparative analysis of the central and peripheral corneal thicknesses using two different imaging systems: Scheimpflug camera and swept-source OCT was performed to investigate the differences in corneal thickness analysis in diabetic patients.

The study group consisted of the 147 eyes of 107 diabetic patients who were examined and compared with 138 eyes of 89 nondiabetic cataract patients. The inclusion criteria for the study group was diabetes mellitus type II identified no less than 10 years ago, with NPDR not requiring prior laser treatment. The control group was recruited from nondiabetic patients. Measurements were obtained on the Pentacam Scheimpflug imaging system and Casia swept-source OCT. All study parameters from anterior chamber images were processed for five different zones, the central zone and four peripherals-superior, inferior, nasal, and temporal. A fit zone diameter of 4 mm was applied for both instruments.

The Pentacam system overestimated corneal measurements in the DM group when compared with the Casia OCT in superior corneal zone (p=0.04), inferior corneal zone (p=0.02), nasal corneal zone (p < 0.001), and temporal corneal zone (p=0.01). In the control group, there were also statistically significant differences between the Pentacam and Casia OCT measured values in inferior corneal zone (p=0.001), nasal corneal zone (p=0.04), and temporal corneal zone (p < 0.001).

Scheimpflug camera pachymetry measurements showed statistically higher CCT values when compared with swept-source OCT measurements.