Comparison of Central Corneal Thickness Measurements Using Ultrasound Pachymetry and Anterior Segment Optical Coherence Tomography

Central corneal thickness (CCT) is a cornerstone parameter in ophthalmology. It influences glaucoma risk assessment, refractive surgery safety margins, and corneal health evaluation. Traditionally, ultrasound pachymetry (USP) has been regarded as the gold standard, but its reliance on corneal contact and topical anesthesia limits its utilisation. Anterior segment optical coherence tomography (AS-OCT), a non-contact imaging modality, offers a high-resolution alternative. This study aimed to compare CCT measurements obtained by USP and AS-OCT in healthy adults, assessing their agreement and clinical interchangeability. Methodology: A cross-sectional study was conducted in 70 healthy adults aged 18–60 years. Each participant underwent CCT measurement by AS-OCT followed by USP, with the average three readings each per eye. To minimize the effect of diurnal variation, all measurements were performed between 10 am and 2 pm. Statistical analyses included paired-sample t-tests, Bland–Altman plots, Pearson correlation, and intra-class correlation coefficients (ICC).