Characterising central serous chorioretinopathy and choroidal thickness in UK Biobank

Abstract

Purpose : Central serous chorioretinopathy (CSR) is part of the pachychoroid spectrum. We present imaging characteristics of eyes graded as CSR compared to controls in UK Biobank (UKBB)

Methods : UKBB prospectively enrolled over 500,000 UK participants aged 40-69. Colour and spectral domain optical coherence tomography (OCT) images of 68517 participants were obtained using Topcon-1000 (Topcon, Japan) and graded masked by certified graders.
Eyes graded as CSR were further analysed for number of fluid areas, fluid height and diameter, serous pigment epithelial detachment (SPED) presence, subfoveal choroidal thickness (SFCT), sub-fluid choroidal thickness (SFLCT), maximum choroidal thickness (MCT), greatest (vertical) choroidal vessel diameter (CVD) on foveal scan and sub-fluid (CVDSF). These were compared to 109 pathology-free matched UKBB eyes. T-tests were used for comparisons, using SPSS v26. Hours of daylight at imaging-time were calculated by deducting time of sunrise (London) on image date from image time

Results : 273 eyes (227 subjects) were graded as CSR; 38 eyes were excluded due to other pathology or inconclusive CSR features, resulting in 235 eyes of 195 subjects (40 bilateral).
Most (88%) had one fluid area, with 8.5% having 2, and 3% with 3 or more areas. In 64%, fluid was extrafoveal, 21% subfoveal and 15% juxtafoveal. Vertical location (within the arcades) was approximately equal between superior, central and inferior. Nasal fluid was most frequent (60%) followed by 22% central and 18% temporal location. Mean fluid height was 89 µm (0-309 µm) and diameter 1073 µm (130-5298 µm). 85% of subjects had no SPEDs, 8.6% had 1, 5.6% 2 or more.
CSR-eyes had significantly thicker mean SFCT and MCT compared to controls (For SFCT: 348 µm (188-502 µm) versus 265 µm (111-443 µm), p<0.001; MCT 394 µm (225-536 µm), 320 µm (176-458 µm) (p<0.001) respectively)). CVD was significantly higher in CSR eyes (181 µm (88-438 µm) versus 165 µm (93-267 µm) for controls (p=0.003)). There was no significant difference between CVD and CVDSF between groups (p=0.708), and no correlation between light-hours at time of imaging and choroidal thickness (for SFCT or MCT, p=0.191 and 0.345)

Conclusions : CFT and MCT were significantly higher in those graded as CSR than controls. Additionally CVD of the largest gradable vessel (foveal scan) was significantly greater in those with CSR, signifying choroidal vascular changes

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.