Fig 1.
Representative cases in each treatment group demonstrating optical coherence tomography angiography (OCTA) of choroidal neovascularization (CNV) in neovascular age-related macular degeneration.
(Left column) The right eye of a 73-year-old male in TEq4-6w group receiving anti-vascular endothelial growth factor (VEGF) therapy with 5 weeks interval (post 77 injections) for type 1+2 CNV (type 2 component is not visualized). CNV morphology is classified as irregular in shape, foveal involving, core vessel present, large loops, and mature form. CNV area is 2.09 mm2 and vessel density is 44%. (Middle column) The right eye of an 83-year-old male in TEq7-12w group receiving anti-VEGF therapy with 11 weeks interval (post 21 injections) for type 1+2 CNV. CNV morphology is classified as irregular in shape, foveal involving, core vessel absent, small and large loops, and mature form. CNV area is 2.18 mm2 and vessel density is 32%. (Right column) The right eye of a 75-year-old male in PRN>12mo group who had not received anti-VEGF therapy for 38 months after 13 injections for type 1 CNV. CNV morphology is classified as circular in shape, foveal sparing, core vessel absent, small loops, and mature form. CNV area is 0.80 mm2 and vessel density is 41%. A-C, En face OCTA image (3 × 3 mm) of outer retinal slab demonstrate well circumscribed neovascular complex. The manually depicted margin of the neovascular complex is shown in yellow line with CNV area. D-F, OCT B-scans showing fibrovascular retinal pigment epithelium detachment with vascular flow overlay. G-I, Binary processed image of the neovascular complex using Otsu algorism. Vessel flow area and vessel density are shown.
Fig 2.
The process of quantifying the percentage of choriocapillaris area of nonperfusion (PCAN) or flow void in eyes with neovascular age-related macular degeneration.
Using Image J software, the en face OCT angiography (OCTA) of the choriocapillaris slab (A) is binarized using “Phansalkar” algorithm (B), black area illustrate the flow void. En face structural OCT of the choriocapillaris slab (C), the RPE elevation map (D), OCTA of the inner retinal slab (E) are all binarized using a specific algorithm and merged supposedly to illustrate the potential area of signal loss at the level of choriocapillaris (F). Subsequently, two images (B and F) are merged to create the final image (G). PCAN is calculated as the percentage of the black area against (black + red) area.
Table 1.
Patients demographics.
Fig 3.
The area of choroidal neovascularization (CNV) on en face OCT angiography by CNV location and the presence of core vessels in all study eyes.
A, A boxplot showing the area of CNV based on the CNV location. Each dot represents one eye. B, A boxplot showing the area of CNV based on the presence of core vessels.
Table 2.
Characteristics of CNV on OCTA by analysis group.
Fig 4.
Comparison in choroidal neovascularization (CNV) appearance on OCT angiography (OCTA) (3 × 3 mm, outer retina slab) observed at retreatment visit and 4 weeks after the treatment in TEq7-12w group.
A-H, Eight eyes with analyzable OCTA at both retreatment visit and 4 weeks after that visit. Some of the vascular components are only visible at retreatment visit (arrow), and a slight dilation of microvasculature is observed at retreatment visit. In two eyes (A and C), the location of CNV was graded as foveal involving due to the presence of pigment epithelial detachment with possible inactive fibrovascular components on B-scan crossing the foveal center.
Fig 5.
Representative cases illustrating en face OCT angiography of the choriocapillaris slab (top row) and the final image created to calculate the percentage of choriocapillaris area of nonperfusion (PCAN) (bottom row) in each group. A, Right eye of a 73-year-old male in TEq4-6w group with type 1+2 choroidal neovascularization (CNV). PCAN is 26%. B, Right eye of an 82-year-old male in TEq7-12w group with type 1 CNV. PCAN is 33%. C, Left eye of an 80-year-old male in PRN>12mo group with type 1 CNV. PCAN is 19%. D, Left eye of a 79-year-old male in the fellow-eye group without a clinical diagnosis of CNV. PCAN is 15%.
Fig 6.
Percentage of choriocapillaris area of nonperfusion (PCAN) in each group and its correlation with cube average thickness.
A, A bar plot representing mean PCAN in each group. Error bars represent standard error of the mean and each dot represents one eye. Mean PCAN was significantly higher in TEq4-6w and TE7-12w group compared with the fellow-eye group. B, Scatter plot representing PCAN versus cube average thickness showing a negative correlation between two variables in all study eyes.