Repeatability Of Dual Rotating Scheimpflug-Placido Camera According To The Topographical Position Of The Cornea

This study aims to investigate the influence of tear meniscus height and TBUT on the repeatability of a dual rotating Scheimpflug-Placido camera in corneal topography assessment across various topographical positions of the cornea.

A prospective observational study was conducted on normal eyes and patients with dry eye syndrome. 

Corneal topography measurements were obtained using a dual-rotating Scheimpflug-Placido camera. Tear meniscus height and TBUT was measured before corneal topography assessment. The Galilei G6, a dual-rotating Scheimpflug-Placido camera, offers comprehensive corneal imaging by capturing test values for 18,002 corneal locations at each measurement. Assessing the repeatability of this device across various corneal locations is crucial for ensuring accurate clinical interpretations. In this study, we utilized MATLAB to analyze the repeatability of each test point provided by the Galilei G6. Each position was assessed multiple times to evaluate repeatability.

In both the normal and dry eye groups, divided based on BUT or the height of the tear film, there were no statistically significant differences in the ratio of unacceptable variation (RUV) and ICC. When plotting the angles and positions from the corneal center of the points where the variability was more than 0.5D or 25um, it was observed that the anterior axial curvature showed a lot of variability even within 3 mm of the center. In the case of posterior axial curvature and corneal thickness, the central area was stable, but variations could be seen in the peripheral areas of the upper and lower cornea. Additionally, it can be observed that overall, the upper cornea exhibits greater variability compared to the lower cornea.

Analyzing the repeatability of the Galilei G6 across 18,002 corneal locations using MATLAB provides valuable insights into the device's reliability for corneal topography assessment. By identifying areas of high variability, clinicians can refine measurement protocols and enhance the accuracy of clinical interpretations. Further research is warranted to elucidate the underlying factors influencing repeatability and develop strategies for improving consistency in corneal topography assessment.