Subfoveal and Parafoveal Choroidal Thickening in Patients with Keratoconus Using the ETDRS Grid on Swept-Source OCT

• Published in: Ophthalmology and therapy 2024-02, Vol.13 (2), p.509-527
• Main Authors: Burguera-Giménez, Neus, Díez-Ajenjo, Mª. Amparo, Burguera, Noemí, Briceno-Lopez, Celeste, Peris-Martínez, Cristina
• Format: Article
• Language: English
• Subjects: Choroidal thickening; ETDRS; Internal Medicine; Keratoconus; Medicine; Medicine & Public Health; Ophthalmology; Original Research; Swept-source optical coherence tomography
• ISSN: 2193-8245; 2193-6528
• DOI: 10.1007/s40123-023-00858-y

Introduction There is growing evidence that confirms morphological changes in the posterior structures in patients with keratoconus (KC); however, isolated alterations could have been missed. This study assesses choroidal thickness (CT) in the fovea and beyond in KC eyes. Methods This prospective case–control and non-randomized study enrolled 107 eyes, 62 eyes of 62 patients with KC, and 45 age-matched eyes of 45 control subjects with axial length in the range of 22–26 mm. Swept-source optical coherence tomography (SS-OCT) was performed to manually measure the subfoveal choroidal thickness (SCT) using a single-line scan. CT was obtained automatically from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid using the 12-lines radial scan pattern. A two-way repeated-measures analysis of variance (ANOVA) was conducted to evaluate CT variations among macular eccentricity, parafoveal area, and the interaction between both factors. CT was compared in all parafoveal areas between groups and subgroups of KC. Results SCT was significantly thicker in KC eyes (357 ± 57 µm) than in healthy eyes (325 ± 63 µm) ( p