Validation and comparison of two commercial OCT systems for in vitro measurement of soft contact lens thickness

J Optom. 2026 Apr-Jun;19(2):100607. doi: 10.1016/j.optom.2025.100607. Epub 2026 Jan 23.

ABSTRACT

PURPOSE: To evaluate the in vitro measurement of central thickness (CT) in soft contact lenses using two commercial optical coherence tomography (OCT) systems by analyzing their repeatability and agreement.

METHODS: A randomized, controlled, investigator-masked trial was conducted using 120 soft contact lenses made from eight different materials. Three examiners measured the CT of the soft contact lenses using two commercial OCT systems with a spherical support marked for correct lens centration. One system was a swept-source OCT, and the other a spectral-domain OCT. Intra- and inter-examiner repeatability were assessed. Comparisons between the OCT systems and the electronic thickness gauge, considered the gold standard, were analyzed. Agreement between the two OCT systems was evaluated using Bland-Altman plots.

RESULTS: Both OCT systems showed a 95% confidence interval for intra-examiner repeatability of <10.0 µm for most materials. Inter-examiner repeatability was worse than intra-examiner repeatability, exceeding 10.0 µm in some materials. The mean differences between the OCT devices and the electronic thickness gauge were <10 µm. Swept-source OCT provided slightly lower CT values than spectral-domain OCT, although most differences were within ± 10 µm.

CONCLUSION: Both OCT systems demonstrate good repeatability and strong agreement with the electronic thickness gauge for measuring the central thickness of soft contact lenses, and can be used interchangeably. These findings support their use as a viable alternative in lens development, manufacturing, and quality control.

PMID:41579490 | PMC:PMC12860703 | DOI:10.1016/j.optom.2025.100607