. Author manuscript; available in PMC: 2017 Oct 20.

Published in final edited form as: N Engl J Med. 2017 Apr 20;376(16):1507–1516. doi: 10.1056/NEJMoa1612836

Table 4.

Effect of Screening Schedules on Delay in the Detection of State 5 Retinopathy.

Schedule	Screening Interval				Average Delay in Detection of State 5 Retinopathy	Average Visits before Detection of State 5 Retinopathy during 20-Yr Period
	State 1	State 2	State 3	State 4
					yr	no.
Practical^*	4 yr	3 yr	6 mo	3 mo	0.42	7.7

Annual (fixed)	1 yr	1 yr	1 yr	1 yr	0.61	18.4

Precise (to the month)^†	5 yr 3 mo	3 yr 7 mo	4 mo	1 mo	0.81	7.4

The practical schedule is described in the text.

^†

The precise schedule is a schedule to the nearest month that limits the probability of proliferative diabetic retinopathy or clinically significant macular edema (state 5 retinopathy) to approximately 0.05.