Geographic filling delay of the choriocapillaris in the region of dilated asymmetric vortex veins in central serous chorioretinopathy

Abstract

Purpose: To investigate the correlation between geographic filling delays in the choriocapillaris using indocyanine green angiography (ICGA) images and dilated vortex veins in central serous chorioretinopathy (CSC).

Design: Observational case series.

Participants: Thirty-two eyes of 32 patients, 21 with acute and 11 with chronic CSC.

Methods: Digital ICGA and fluorescein angiography (FA), with videoangiography, and swept-source optical coherence tomography (SS-OCT) for B-scan and en-face choroidal imaging were performed. Overlapping of the filling delay areas in the choriocapillaris in the early-phase ICGA images and the region of dilated vortex veins in the en-face images were analyzed. The consistency of both areas was graded as follows. Grade 3: filling delay area is entirely involved in the dilated vortex vein region. Grade 2: 50% or more of filling delay area overlaps with the dilated vortex vein region. Grade 1: less than 50% of filling delay area overlaps with the dilated vortex vein region. Grade 0: no tendency for overlapping of two areas. We evaluated the asymmetry of upper and lower vortex veins in en-face images of the Haller layer. Using the binarization method, we quantified the luminal and stromal areas of the choroid. The ratios of the Haller layer area and luminal areas in the Haller layer to total choroidal area were examined.

Results: The consistency of overlapping of the two areas was grade 2.62 ± 0.49 in acute CSC and grade 1.55 ± 0.78 in chronic CSC (p = 0.0005). Asymmetry of upper and lower vortex veins was seen in 17 of 22 eyes (81%) with acute CSC and 6 of 11 eyes (54.5%) with chronic CSC (p = 0.114). Central choroidal thickness was 411 ± 79 μm in acute CSC and 326 ± 64 μm in chronic CSC (p = 0.004). In the posterior fundus with a 4500 μm diameter, the ratio of the Haller layer area to total choroidal area was 63.7 ± 8.6% in acute CSC and 57.1 ± 7.9% in chronic CSC (p = 0.047). The ratio of the luminal area in the Haller layer area to total choroidal area was 46.9 ± 7.6% in acute CSC and 40.0 ± 6.9% in chronic CSC (p = 0.014).

Conclusion: Filling delay areas in the choriocapillaris and dilated vortex vein regions showed marked overlapping in acute CSC. Increased choroidal thickness was attributed to dilated vortex veins. These findings suggest that the blood flow into the choriocapillaris is delayed as a result of congestion of the dominant vortex veins that supply this geographic area. CSC may be a disease characterized by vortex vein congestion that develops in eyes with asymmetric vortex veins.

Fig 1. Case 1, a 36-year-old man, had acute central serous chorioretinopathy in the left eye of.

The best-corrected visual acuity was 0.7 with -3.5 diopters of myopia. A, Color fundus photograph shows serous retinal detachment in the macula. B-E, Indocyanine green angiography (ICGA) images at 1, 2, 6, and 23 seconds (s) from the entrance of dye into the fundus. A choroidal filling delay is seen at the arteriolar (B) and choriocapillaris phases (C). The macula remains dark during the venous (D) and late phases (E). D, A filling delay is seen in the inferior vortex vein (red arrows) at 6s. F, Fundus autofluorescence shows accumulation of hyperfluorescent material in the inferior subretinal space. G, Horizontal swept-source optical coherence tomography B-scan image shows the pachychoroid (central choroidal thickness; 471μm) with markedly dilated vortex veins and a serous retinal detachment with an elongated photoreceptor outer segment. H, Vertical B-scan shows findings similar to those of the horizontal B-scan. I, ICGA image at 2s shows filling delay area in the choriocapillaris outlined in yellow. J, An en-face image of the choroid at the plane containing the dominant vortex vein, the region of which is outlined in blue. K, Superimposition of the filling delay area (yellow line) onto the dilated vortex vein region (blue line) is shown. Overlapping of the two areas is grade 3. L, Late-phase fluorescein angiography image. The leakage site within the yellow circle is at the distal end of the dilated vortex vein in J.

Fig 2. Case 2, a 39-year-old man, had acute central serous choriocapillaris in the left eye.

The best-corrected visual acuity is 1.2 with emmetropia. A, Color fundus photograph shows a serous retinal detachment in the posterior pole. B-E, Indocyanine green angiography images at 0 (B), 1 (C), 4 (D), and 28 seconds (s) (E) from the entrance of the dye into the fundus. B, During the arteriolar phase, a filling delay is seen in the nasal half of the posterior fundus. C, During the choriocapillaris phase, a vertical filling delay is seen nasal to the fovea. D, The superior half of the zone remains dark even in the venous phase. E, The dark area becomes obscured. Hyperfluorescence is seen in a dilated vortex vein (yellow arrow) that corresponds to the leakage point on a fluorescein angiography image, as indicated by the yellow circle in L. F, Fundus autofluorescence shows increased fluorescence in the area of the serous retinal detachment. G, H, Swept-source optical coherence tomography B-scan image, in the horizontal (G) and vertical sections (H), shows a serous retinal detachment with pachychoroid (central choroidal thickness; 459μm). Marked dilatation of the vortex veins (yellow arrows) is seen superior to the macula in H. I, Geographic area of the filling delay at the choriocapillaris phase in C is outlined in yellow. J, An en-face image of the choroid at the plane containing the dominant vortex vein, the region of which is outlined in blue. K, Superimposition of the filling delay area (yellow line) on the dilated vortex vein region (blue line) is shown. Overlapping of the two areas is grade 3. L, Late-phase fluorescein angiography. The leakage site in the yellow circle is on the dilated vortex vein in J.

Fig 3. Case 3, 48-year-old man, had chronic central serous chorioretinopathy in the left eye.

The best-corrected visual acuity is 0.5 with +1.25 diopters of hyperopia. A, Color fundus photograph shows yellow precipitates at the macula and zonal atrophy with yellowish spots corresponding to the old descending track of subretinal fluid. B-E, Indocyanine green angiography (ICGA) images at 1 (B), 2 (C), 6 D), and 29 seconds (s) (E) from entrance of the dye into the fundus. B, Arteriolar phase. C, A large filling delay is seen in the vertical zone between the disc and macula and the horizontal zone including the macula and its temporal vicinity. D, The filling delay in C remains dark during the venous phase. E, The filling delay is obscured. Hyperfluorescence (yellow arrow) is seen at the dilated vortex vein, which corresponds to the leakage on the fluorescein angiography image (L). F, Fundus autofluorescence shows hyperfluorescent dots and a focal area of hypofluorescence in the area of the old lesion. G, H, Horizontal (G) and vertical (H) detachment with marked dilatation of the vortex vein (yellow arrows in G) in the macula and nasally. The choroid shows pachychoroid (central choroidal thickness; 423 μm). I, ICGA image of the choriocapillaris phase at 1.5s. The filling delay area is outlined in yellow. J, An en-face image of the choroid at the plane containing the dilated dominant vortex vein. The dilated vortex vein region is outlined in blue. K, Superimposition of the filling delay area (yellow line) on the dilated vortex vein region (blue line) is shown. The extents of both areas were ill defined but approximately overlapped. Overlapping is grade 2. L, Late-phase fluorescein angiography. The yellow circle indicates the leakage site, which corresponds to the distal end of the dilated vortex vein (J). Hyperfluorescence is seen in the area of the descending tract due to a window defect in the atrophic retinal pigment epithelium.

Fig 4. Case 4, a 77-year-old woman, had chronic central serous chorioretinopathy in the left eye.

The best-corrected visual acuity is 0.6 with +2.75 diopters of hyperopia. A, Color fundus photograph shows diffuse drusen in the posterior pole. B-E, Indocyanine green angiography images at 1 (B), 2 (C), 5 (D), and 26 seconds (s) (E) from entrance of the dye into the fundus. A filling delay is seen in the inferotemporal quadrant at the arteriolar (B) and choriocapillaris phases (C). This area remains dark in the venous (D) and late phases (E). F, Fundus autofluorescence image shows weak hyperfluorescence in the inferotemporal quadrant. G, H, Horizontal (G) and vertical (H) swept-source optical coherence tomography B-scans show a small serous retinal detachment temporal (G) and inferior to the fovea (H). The choroid has no pachychoroid (central choroidal thickness; 357μm) but the vortex veins are moderately dilated. I, Filling delay area in the choriocapillaris in C is outlined in yellow. J, An en-face image of the choroid at the plane containing the dominant vortex veins, the region of which is outlined in blue. K, Superimposition of the filling delay area (yellow line) on the dilated vortex vein region (blue line) is shown. Extent of the filling delay area is ill defined. The area is larger than the dilated vortex vein region. Overlapping of the two areas is grade 2. L, Late-phase fluorescein angiography. The yellow circle indicates the site of dye leakage corresponding to the dilated vortex vein in J. The hyperfluorescent spots indicate the presence of multiple drusen.