Analysis of Widefield Choroidal Thickness Maps of Healthy Eyes using Swept Source Optical Coherence Tomography

Abstract

Abstract We aimed to obtain widefield (WF) swept source optical coherence tomography (SS-OCT) data and examine the features of choroidal thickness maps of healthy eyes. The posterior pole choroidal thickness was examined for 127 eyes using enhanced-depth imaging (EDI) of SS-OCT with a viewing angle of 20 (vertical) × 23 (horizontal) mm, and choroidal thickness maps were generated. For SS-OCT image analysis, we developed a grid with inner and outer rings, each divided into superotemporal, inferotemporal, superonasal, and inferonasal quadrants, respectively, making up a total of nine subfields including the central 3-mm ring. The posterior pole choroidal thicknesses were significantly lesser at the periphery than in the central area, in the inferior field than in the superior field, and in the nasal field than in the temporal field (p < 0.001 for all). We also evaluated the effects of age and axial length (AL) on the WF choroidal thickness. Choroidal thicknesses in all subfields were negatively associated with advanced age (p < 0.05). Choroidal thicknesses in the central subfield and the inferonasal inner and outer subfields were negatively associated with AL (p = 0.042, 0.034, and 0.022, respectively). These findings provide insights into the two-dimensional characteristics of the choroidal thickness and their associations with age and AL.