Choriocapillaris flow deficit and the location of pachyvessels.

(A) An averaged en face OCTA image of the choriocapillaris within a 3 × 3 mm area. Arrowheads show the choriocapillaris flow deficit. (B) An en face OCT image of the choroid within a 3 × 3 mm area. Asterisks show pachyvessels. (C, D) These two en face images were binarized using automatic local thresholding with the Phansalkar method for the choriocapillaris slab (C) and the choroid slab (D), respectively. (E) With inversion, the black area that shows flow voids was converted to a white area and then colored in red. (F) With inversion, the black area that shows pachyvessels was converted to a white area and then colored in green. (G) Composite image of these two en face images. The flow void is red, and the pachyvessel is green. The yellow area shows the choriocapillaris flow deficit just above the pachyvessels. The red area shows the choriocapillaris flow deficit outside the pachyvessels. This composite image shows that the choriocapillaris flow deficit is seen not only just above the pachyvessels but outside pachyvessels. The portion of the flow void area overlying the pachyvessels (yellow area) against the whole flow void area of the choriocapillaris was 23.68%.