Repeatability of Corneal Aberrations and Ocular Biometry Measurements Using the Pentacam® AXL: A Cross-sectional Study

Abstract

Introduction: Accurate assessment of ocular biometry and corneal aberrations for diagnosis and therapy is crucial in many clinical settings. Devices to improve the measurements of these parameters are constantly being developed. Aim: To evaluate the repeatability of ocular biometry and corneal aberrations obtained by the Pentacam® AXL in normal eyes. Materials and Methods: This cross-sectional study was conducted in the Optometry Department of King Saud Universiy, Riyadh, Saudi Arabia from September 2021 to February 2022. The study included a total of 120 eyes from 60 normally sighted adult participants whose of ocular biometry and corneal aberrations were measured three times in a single session using the Pentacam® AXL. Biometric parameters include Axial Length (AL), mean K-reading (Km), Anterior Chamber Depth (ACD), Central Corneal Thickness (CCT), and Horizontal White-to-White Distance (HWTW). The aberrometry parameters include the most significant corneal higher-order aberrations (coma, trefoil, spherical aberration), and the Root Mean Square (RMS) of the higher-order aberrations. Repeatability was assessed using within-subject Standard Deviation (SDw), the repeatability limit (r), and the Intraclass Correlation Coefficient (ICC). Results: The current study included 120 eyes of 60 subjects with a mean age of 21±2.08 years (range: 18 to 28 years). The repeatability was good for all recorded biometric measurements, with the most repeatable being AL (r=0.028, SD=0.01). All values of ICC for biometric measurements revealed excellent repeatability, being over 0.994. In addition, coma and spherical aberrations had excellent repeatability with ICC ≥0.935, and RMS, trefoil, secondary astigmatism, and quadrafoil aberrations had good repeatability with ICC 0.938, 0.823, 0.898, and 0.827, respectively. Conclusion: The Pentacam® AXL demonstrated good repeatability for ocular biometry and corneal aberrations in healthy eyes.

Keywords

• axial length
• non contact biometry
• ocular aberrations
• partial coherence interferometry