Comparison of Retinal Layer Thickness and Capillary Vessel Density in the Patients with Spontaneously Resolved Acute Central Serous Chorioretinopathy

Abstract

We investigate retinal layer thickness and capillary vessel density (VD) in the patients with central serous chorioretinopathy (CSC) who recovered spontaneously and evaluate the correlation between the changes in these values and visual outcomes using swept-source optical coherence tomography (SS-OCT) and OCT angiography (OCTA). This retrospective case-control study included 34 eyes of 34 patients with spontaneously resolved acute CSC. The changes in retinal layer thickness and capillary VD were examined using SS-OCT and OCTA after complete resolution of subretinal fluid (SRF). The fellow eyes and 34 healthy eyes were used as controls. In the eyes with CSC, the outer retinal layer was significantly thinner than in the eyes of fellow and healthy controls. The foveal avascular zone area and VDs in the superficial and deep capillary plexus in the eyes with CSC were not significantly different from those in the eyes of fellow and healthy controls. The VD of the choriocapillaris in the eyes with CSC was significantly lower than that in the eyes of fellow and healthy controls. Correlation analyses revealed that the outer retinal layer thickness and initial visual acuity were positively correlated with the final visual acuity. Furthermore, the initial SRF area and height were negatively correlated with the outer retinal layer thickness after SRF resolution. Attenuation of outer retinal layer thickness and decreased VD of the choriocapillaris were observed in the eyes with spontaneously resolved acute CSC. The outer retinal layer thickness could be an important visual predictor of CSC.

Keywords: capillary vessel density; central serous chorioretinopathy; choriocapillaris; optical coherence tomography; optical coherence tomography angiography; vessel density.

Figure 1

Fundus photography and optical coherence tomography (OCT) images in a 34-year-old man with acute central serous chorioretinopathy (CSC) showing serous retinal detachment (SRD) at the initial examination ((A) fundus photography; (B) OCT image), spontaneous resolution of subretinal fluid (SRF) after 1 month ((C) fundus photography; (D) OCT image)), and unaffected fellow eye ((E) fundus photography; (F) OCT image). The mean logarithm of the minimal angle of resolution (logMAR) best-corrected visual acuity was 0.00 (Snellen equivalent: 20/20) at the initial SRD phase and 0.00 (20/20) after spontaneous SRF resolution. Visual acuity in the fellow eye was 0.00 (20/20).

Figure 2

Measurements of subretinal fluid (SRF) height and area were calculated at the initial visit using the 12 radial wide scan and three-dimensional (3D) wide continuous swept-source optical coherence tomography (SS-OCT) mode. The SRF height was defined as the difference between mean total retinal thickness (A, top image) and mean neurosensory retinal thickness (A, bottom image) at 1 mm diameter center circle in nine Early Treatment Diabetic Retinopathy Study subfields. The measurements of each layer thickness were performed by semi-automated segmentation with manual corrections using the 12 radial wide scan (A). For measurement of SRF area, the 3D OCT scans were reconstructed as en face images. The reference slabs were aligned and flattened to the level of the inner/outer segment. The SRF area was defined as the area inside with contrast change at this level (B).

Figure 3

Measurements of the foveal avascular zone (FAZ) area and capillary vessel density (VD) were conducted using swept-source optical coherence tomography angiography (SS-OCTA). En face images were generated for retinal vascular networks: superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC), after spontaneous resolution of subretinal fluid (SRF) 1 month later (A1–C3), and in unaffected fellow eyes (D1–F3). The cross-sectional scans show the corresponding segmentation layers and intact inner or outer segment junction (A1–F1). The FAZ area was defined as the area inside the central border of the capillary network and determined by manually outlining the inner border of foveal capillaries using the OCTA system software (A2,B2,D2,E2). The VD maps consisted of concentric circles with diameters of 1 and 3 mm. Foveal and parafoveal VDs of SCP, DCP, and CC were measured automatically (A3–F3).

Figure 4

Relationship between the amount of subretinal fluid (SRF) (area and height) and outer retinal layer thickness, as determined using Spearman’s correlation coefficient analyses, in the eyes with acute central serous chorioretinopathy (CSC), showing serous retinal detachment (SRD) at the initial examination. The SRF area was moderately and negatively correlated with outer retinal layer thickness (ρ = −0.510, p = 0.002; (A)). The SRF height was also moderately and negatively correlated with outer retinal layer thickness (ρ = −0.472, p = 0.005; (B)).