Table 4.

Grades of macular capillary non-perfusion (CNP)

Lesion	Grading	Definition	Figures
Macular CNP	Cannot grade	No gradeable images of the macula exist	None
	Absent	One or more gradeable images of the macula exist, and no CNP is seen at the macula on any of these images	None
	Grade 1	A few, small areas of CNP (≥63 µm MLD) are seen, often around the foveal avascular zone	5, 6
	Grade 2	Combined area of CNP is up to ~1/3 of a disc area	7, 8
	Grade 3	Combined area of CNP is approximately 1/3–1 disc area	9, 10
	Grade 4	Combined area of CNP at the macula exceeds 1 disc area. This can be due to a few large areas or many smaller areas of CNP	11, 12