Repeatability of 3D OCT Pachymetry in Eyes with and without Contact Lens Induced Corneal Swelling

Abstract

Introduction: Corneal thickness measurement is an indirect assessment of the physiological corneal function in human eye. This value, especially in the central area, is an important data for clinical diagnosis, treatment and monitoring of anterior segment pathologies. There are several technologies for non-invasively measuring corneal thickness like optical coherence tomography (OCT). However, there is little information available describing the effect of contact lens induced corneal swelling in OCT measures. The purpose of this study was to evaluate the repeatability of OCT corneal pachymetry in eyes with and without contact lens induced corneal swelling. Material and Methods: This study included five visits over one week in six healthy subjects: baseline and after sleeping with four different CL of +0.50 D, +2.00 D, +5.00 D and +8.00 D (Acuvue 2, Johnson & Johnson Vision Care) on four different days. Corneal pachymetry OCT 3D (Topcon) were measured three consecutive times during each visit. Besides, this measurement was repeated in 12 meridians (Scans #1 to #12), between 0°and 165°with 15° intervals. Results: Corneal pachymetry was significant different between before and after contact lens wear (p < 0.001 ANOVA). High repeatability was found without corneal swelling [Coefficient of variation (CV) = 0.68% p = 0.93] and with corneal swelling [CL -0.50 D (CV = 0.78% p = 0.95; 590 ± 46 μm CI 95% 548 to 596), with CL + 2.00 D (CV = 0.72% p = 0.97; 601 ± 46 μm CI 95% 595 to 607), with CL + 5.00 D (CV = 0.78% p = 0.66; 608 ± 50 μm CI 95% 601 to 615) and with CL + 8.00 D (CV = 0.77% p = 0.97; 607 ± 44 μm CI 95% 601 to 613)]. There were no differences (p = 1.00) in central corneal thickness along the 12 scans corneal [Scan #0 (593 ± 50 μm CI 95% 582 to 603), #1 (592 ± 50 μm CI 95% 581 to 603), #2 (591 ± 50 μm IC 95% 580 to 602), #3 (590 ± 49 μm CI 95% 579 to 600), #4 (590 ± 50 μm CI 95% 579 to 600), #5 (591 ± 50 μm CI 95% 581 to 602), #6 (590 ± 51 μm CI 95% 580 to 601), #7 (589 ± 50 μm CI 95% 578 to 600), #8 (590 ± 50 μm CI 95% 579 to 600), #9 (589 ± 50 μm CI 95% 579 to 600), #10 (592 ± 50 μm CI 95% 581 to 602) and #11 (591 ± 50 μm CI 95% 580 to 601). Conclusions: 3D OCT showed a high repeatability (CV < 1%) to measure central thickness in corneas with and without contact lens induced corneal swelling. This technology presents advantages over other clinical devices used to measure corneal thickness and could be the “gold standard” for future clinical studies and clinical practice for eye care practitioners.