Table 5.

Relation of Drusen Type and Drusen Size at Baseline to the Four-year Incidence of Age-Related Macular Degeneration (AMD) Drusen by Type in the Right Eye

	Four-year Incidence of AMD Drusen by Type
	Hard Distinct			Soft Distinct			Soft Indistinct
	N	n	% (CI)	N	n	% (CI)	N	n	% (CI)
Baseline Drusen Type
None or hard indistinct	523	322	61.6 (57.4, 65.7)	552	29	5.3 (3.4, 7.11)	554	2	0.4 (0.2, 3.2)
Hard distinct			*	2664	177	6.6 (5.7 7.6)	2691	27	1.0 (0.6, 1.4)
Soft distinct			*			*	414	27	6.5 (4.1, 8.9)
Soft indistinct			*			*			*
Baseline Drusen Size (maximum diameter in μm)
None or questionable	523	322	61.6 (51.8, 65.2)	552	29	5.3 (3.4, 7.1)	554	2	0.4 (0.1, 0.9)
<63			*	2287	102	4.5 (3.6, 5.3)	2300	13	0.6 (0.3, 0.9)
≥63 to <125			*	377	75	20.0 (15.9, 23.9)	599	31	5.2 (3.4, 7.0)
≥125 to <250			*			*	179	8	4.5 (1.4, 7.5)
≥250			*			*	27	2	7.4 (2.5, 17.3)

N=number at risk at baseline, n=number of incident cases, CI=confidence interval.

Note: Data presented as incidence of specific drusen type for each category of baseline drusen type or baseline drusen size. Four-year changes are similar for both right and left eyes. Four-year changes are similar for both right and left eyes.

^*Not applicable. Participants can only be at-risk for incidence of drusen type of greater severity given a less severe drusen type or drusen size at baseline. For instance, participants with baseline drusen size ≥63 μm to <125 μm may develop incident soft distinct or soft indistinct drusen, but not incidence hard distinct drusen which is of lesser severity than their baseline drusen of that particular size.