Fig 1.
The analysis process of the en-face OCTA image.
The 3 mm × 3 mm-sized en-face image of the SCP (A) and DCP (B) was converted to a binarized image (D and E) using ImageJ software. From the binarized image, the FAZ area (black dotted grayish area) was measured at the center, and the black colored vessel area was measured. Vessel density was obtained by dividing the vessel area by the area where the FAZ area was removed by 9 mm2. The signal void (F) of the choriocapillaris at 6 months post-PDT is smaller than the signal void (C) of the choriocapillaris after the subretinal fluid was completely absorbed 1 month post-PDT.
Fig 2.
Horizontal section of OCT image and OCTA image of SCP of a 67-year-old man in the incomplete recovery group (A, B, C) and 63-year-old man in the complete recovery group (D, E, F). Compared with the 67-year-old man (incomplete recovery group), the 63-year-old man (complete recovery group) had better BCVA at baseline and 6 months after PDT (logMAR BCVA, 0.05 vs. 0.22 and 0.05 vs. 0.10, respectively), and shorter symptom duration (4 months vs. 7 months, respectively). Moreover, the central foveal thickness before (A, D) and after (C, F) PDT was thicker (182 μm vs. 145 μm and 201 μm vs. 135 μm, respectively), and the SCP FAZ area (B, E) before PDT was narrower (0.22 mm2 vs. 0.32 mm2, respectively).
Table 1.
Comparison of baseline demographics and clinical characteristics between the two groups.
Table 2.
Comparison of sequential characteristics by groups and by the visit.
Fig 3.
Receiver operating characteristic curves of baseline CFT and SCP-FAZ.
The area under the curve was 0.858 for CFT and 0.816 for SCP FAZ. The cutoff value (asterisk) using the Youden index was 139.5 μm for CFT and 0.265 mm2 for SCP FAZ. CFT, central foveal thickness; SCP, superficial capillary plexus; FAZ, foveal avascular zone.
Fig 4.
Graphs showing the correlation between variables before PDT (CFT, SCP FAZ, and DCP FAZ) and baseline BCVA, 6 months post-PDT BCVA, and BCVA changes over 6 months.
BCVA-related variables show a significant correlation with both SCP FAZ and DCP FAZ (all p < 0.01). CFT, central foveal thickness; SCP, superficial capillary plexus; DCP, deep capillary plexus; FAZ, foveal avascular zone; R, Spearman’s rho coefficient; BCVA, best corrected visual acuity; logMAR, logarithm of the minimum angle of resolution; PDT, photodynamic therapy.