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. Author manuscript; available in PMC: 2006 Jun 1.
Published in final edited form as: Arch Ophthalmol. 2005 Nov;123(11):1484–1498. doi: 10.1001/archopht.123.11.1484

Table 8.

Definitions of Scale Steps

Step Drusen Area Increased Pigment Depigmentation-GA
1 <C-1 0 0
2 ≥C-1, <C-2 0 0
<C-1 ≥Q and/or ≥Q, <I-2
3 ≥C-2, <I-2 0 0
4 I-2, <O-2 0 0
≥C-1, <I-2 ≥Q and/or ≥Q, <I-2
<C-2 ≥0 ≥I-2, <0.5 DA
5 ≥O-2, <0.5 DA 0 0
≥I-2, <O-2 ≥Q ≥Q, <I-2
≥C-2, <I-2 ≥0 and/or ≥I-2, <0.5 DA
6 ≥0.5 DA 0 0
≥O-2, <0.5 DA ≥Q and/or ≥Q, <I-2
≥I-2, <O-2 ≥0 ≥I-2, <0.5 DA
7 ≥0.5 DA ≥Q and/or ≥Q, <I-2
≥O-2, <0.5 DA ≥0 ≥I-2, <0.5 DA
8 ≥0.5 DA ≥0 ≥I-2, <0.5 DA
Any ≥0 ≥0.5 DA
9 Any ≥0 Noncentral GA

Abbreviations: DA, disc area; GA, geographic atrophy.