Table 3 Detection rates with 95% confidence intervals (CI) by eye and by image for manual and for automated “disease/no disease” grading for each of the grades assigned by the reference standard, with frequency of occurrence of each grade as a percentage of the total 13 398 eyes.

Grades assigned by reference standard	Frequency of occurrence (%)	Manual: by eye		Automated: by eye		Automated: by image
		“Disease/no disease” grading detection rate (CI)	Missed cases	“Disease/no disease” grading detection rate (CI)	Missed cases	“Disease/no disease” grading detection rate (CI)	Missed cases
R1 (Mild background retinopathy)	19.6	76.8% (75.1–78.3) 2019/2630	611	80.0% (78.4–81.4) 2103/2630	527	80.4% (78.8–81.8) 2211/2751	540
M1 (Observable maculopathy)	0.9	96.6% (91.5–98.7) 112/116	4	94.0% (88.1–97.0) 109/116	7	94.4% (88.8–97.2) 117/124	7
R2 (Observable background retinopathy)	0.1	100% (80.6–100) 16/16	0	93.8% (71.7–98.9) 15/16	1	94.7% (75.4–99.1) 18/19	1
M2 (Referable maculopathy)	1.9	98.4% (95.9–99.4) 245/249	4	94.0% (90.3–96.3) 234/249	15	93.8% (90.2–96.1) 255/272	17
R3 (Referable background retinopathy)	0.4	95.8% (86.0–98.8) 46/48	2	97.9% (89.1–99.6) 47/48	1	98.0% (89.7–99.7) 50/51	1
R4 (Proliferative retinopathy)	0.3	100% (90.4–100) 36/36	0	94.4% (81.9–98.5) 34/36	2	95.2% (84.2–98.7) 40/42	2
R6 (Technical failure)	5.0	90.6% (88.1–92.6) 606/669	24	99.4% (98.5–99.8) 665/669	4	98.4% (97.4–99.0) 963/979	16