Table 4 Grades of macular capillary non-perfusion (CNP)

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