A comparison of choroidal thicknesses between pachychoroid and normochoroid eyes acquired from wide‐field swept‐source OCT

Abstract

Purpose We investigated the wide‐field choroidal thickness (CT) using swept‐source optical coherence tomography (SS‐OCT) and compared the characteristics of the choroidal layer between pachychoroid and normochoroid groups. Methods A total of 120 eyes from 120 normal subjects were included. All subjects were divided into two groups according to the subfoveal CT (≥300 μm, pachychoroid group; <300μm, normochoroid group). All subjects underwent an HD spotlight 16 mm scan using SS‐OCT. The CT was measured at the following 12 points: subfoveal, 3 points in the nasal peripapillary area, 6 points in the macular area and 2 peripheral points at 5400 and 8100 µm from the fovea. The CT measurements were compared between the two groups, and statistical analyses were performed to determine clinical factors associated with each point of the CT. Results The CT in the pachychoroid group was thicker than that in the normochoroid group at all points (p < 0.01). The CTs of the two groups in the macular area were highly associated with the subfoveal CT. However, the CTs of the nasal peripapillary and peripheral areas showed lower associations with the subfoveal CT and lower diagnostic abilities for the pachychoroid group. The existence of pachyvessels was found to be a significant factor causing the regional variations. Conclusions The CTs in the peripapillary and peripheral areas showed different patterns than the subfoveal CT. Regional variations by pachyvessels were more frequent in the peripapillary and peripheral areas than in the macular area, and the subfoveal CT did not represent the whole choroidal area.

Wide-Field Swept-Source Optical Coherence Tomography Analysis of Interocular Symmetry of Choroidal Thickness in Healthy Young Individuals

“…To measure the CTs of the nasal peripapillary and peripheral areas, wide-field imaging is required, rather than the modality commonly used in OCT. Several studies have measured peripheral choroidal CTs using wide-field imaging. [35][36][37]39,40 However, it is difficult to compare CTs with other studies of nasal peripapillary and peripheral areas because CTs were measured at different locations, based on methodological differences. Furthermore, most previous studies included analyses of interindividual variation or topographically intraindividual variation, rather than interocular comparison.…”

“…CT measurements were conducted in the manner described in our previous study. 35 In the HD spotlight 16-mm scan, measurements were made at 12 points: 3 points at a distance of 900 μm, 1800 μm, and 2700 μm from the Bruch's membrane opening of nasal optic disc margin (nasal points 3, 2, and 1, respectively; nasal peripapillary area), 1 point at the subfovea, 6 points at a distance of 900 μm, 1800 μm, and 2700 μm from the subfovea to the nasal and temporal areas (nasal point 6 and temporal point 1, nasal point 5 and temporal point 2, and nasal point 6 and temporal point 3, respectively; macular area), and 2 points at a distance of 2700 μm, and 5400 μm from the temporal point 3 (temporal points 4 and 5, respectively; peripheral area; Fig. 1).…”

Wide-field Swept-source OCT Analysis of Interocular Symmetry of Choroidal Thickness in Subjects with Uncomplicated Pachychoroid

“…Thus, AL may have a greater effect on CT in the macular area than in the nasal peripapillary and peripheral areas, as suggested by previous studies. 28,32 Other factors, such as age, sex, IOP, and SE, also showed no relationships with interocular CT differences. However, only young adults were included in our study, and the age range was narrow (24-35 years; mean age = 27.55 years), which limited the generalizability of the ndings.…”

“…However, the reason for these differences is not clear. In our previous study, 32 CT measurements were compared between pachychoroid and "normochoroid eyes" using wide-eld SS-OCT. Even in pachychoroid eyes, pachyvessels were sometimes absent from the nasal peripapillary and peripheral areas, leading to smaller than expected CT values.…”

“…CT measurements were conducted in the same manner as described in our previous report. 32 For the 16mm HD spotlight scan, CT was measured from the outer part of the hyperre ective line (corresponding to the retinal pigment epithelium RPE) to the inner surface of the sclera, using a caliper and built-in review software. Measurements were made at 12 points: 3 points at 900-µm intervals from the nasal optic disc margin (nasal points 1-3; nasal peripapillary area), 1 point at the subfovea, 6 points at 900-µm intervals from the fovea to the nasal and temporal areas (nasal points 4-6; temporal points 1-3; macular area), and 2 points at 2,700-µm intervals from temporal point 3 (temporal points 4 and 5; peripheral area) ( Fig.…”