Clinical Ophthalmology (Oct 2017)
Variability of choroidal and retinal thicknesses in healthy eyes using swept-source optical coherence tomography – implications for designing clinical trials
Abstract
Albert Caramoy,1 Ludwig M Heindl2 1Eye Center Wolfsburg-Fallersleben, Wolfsburg, 2Department of Ophthalmology, University of Cologne, Cologne, Germany Aim: The aim was to study the variability of choroidal scleral interface (CSI) thickness in healthy subjects and its relevance for designing future studies. Methods: A total of 123 volunteers were imaged using swept-source optical coherence tomography. Early treatment diabetic retinopathy grid was used. Results: Mean central retinal thickness was 285.85±14.53 µm and 287.18±12.93 µm, and mean central CSI thickness was 273.94±77.77 µm and 271.19±78.85 µm for the right and left eyes, respectively. Mean retinal and CSI thicknesses correlated negatively with age (p=0.023, r=–0.208 and p<0.0001, r=–0.426, respectively) and axial length (p=0.016, r=–0.220 and p<0.0001, r=–0.504, respectively). To detect a CSI change of at least 112 µm, a sample size of 11 or 36 per group is needed for a single- or double-arm study, respectively (α=0.05, power =0.90, no loss to follow-up, assuming standard deviation in future studies as 100 µm). Conclusion: Future clinical studies using CSI as end point are possible with regard to sample size needed. Keywords: swept-source optical coherence tomography, choroidal thickness, retinal thickness, clinical trials
