AREDS Report no. 18 described a simplified clinical scale that defines risk categories for the development of advanced AMD.

The grading system described assigns one risk factor to each eye for the presence of one or more large drusen (125 microns) and one risk factor for the presence of any pigment abnormality.

If no large drusen are present, the presence of intermediate drusen in both eyes is counted as one risk factor.

Advanced AMD in one eye is counted as two risk factors; if this is observed together with large drusen and hypo/hyperpigmentary changes in the RPE, four risk factors are considered, which corresponds to the highest risk level for patients with AMD.

Risk factors are added for both eyes, leading to a 5-stage risk of developing advanced AMD in at least one eye increases as follows⁽¹¹⁾:

Stage 0 (zero factors) – 0.5% in five years

Stage 1 (one factor) – 3% in five years

Stage 2 (two factors) – 12% in five years

Stage 3 (three factors) – 25% in five years

Stage 4 (four factors) – 50% in five years⁽¹¹⁾