Three-Dimensional Choroidal Contour Mapping in Healthy and Diseased Eyes

Quantitative evaluation of choroidal curvature including choroidal inner boundary (CIB) and choroidal outer boundary (COB) and report a comparison between healthy and diseased eyes.

This retrospective study was conducted on 97 eyes of 97 patients. Eyes were divided into three groups: central serous chorioretinopathy (CSCR), dry age-related macular degeneration (AMD), and healthy eyes. Delineation of CIB and COB was performed using a hybrid method based on our previously validated deep learning and three-dimensional (3D) smoothing methods for choroidal layer segmentation. Quantitative analysis of the surfaces was based on best-fit spherical radius (R). R for overall surface, as well as for each region (central/nasal/temporal/superior/inferior region), was estimated. Statistical analysis was done using SPSS software.

There were 35 healthy eyes, 32 eyes with CSCR, and 30 eyes with dry AMD. At CIB and COB; RCSCR > Rhealthy > RAMD (P ≤ 0.001). The central region had the lowest R among all the regions within a group at CIB and COB (P < 0.001) in healthy, CSCR, and AMD eyes. There was moderate positive correlation of R of CIB and COB with subfoveal choroidal thickness in healthy eyes and a negligible/weak correlation in CSCR and AMD eyes.

Contour of choroid at CIB and COB was the flattest in CSCR and steepest in AMD. Central region was the steepest among all sectors in both healthy and diseased eyes.

Quantitative study of surface at CIB and COB in diseases helps in understanding the pathophysiological changes and provides a clinical biomarker in disease monitoring and treatment as well.