Table 1.
Agreement (Bland-Altman and Weighted Kappa) of optic disc VCDR scores between different imaging modalities and different graders. The comparison number relates to the specific comparisons that are described in the methodology section.
| Comparison Number | Reference Image | Comparison Image | Number | VCDR |
Weighted Kappa (SD) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean Difference | 95% limits of agreement | ||||||||||
| Camera | Grader | Screen | Camera | Grader | Screen | Upper | Lower | ||||
| 1 | DRS | Expert | Large | DRS | Expert | Large | 100 | -0.07 | 0.07 | -0.21 | 0.90 (0.01) |
| 2 | Peek | Expert | Large | Peek | Expert | Large | 100 | -0.01 | 0.16 | -0.18 | 0.77 (0.04) |
| 3a | DRS | Expert | Large | Peek | Ophth | Phone | 100 | -0.08 | -0.11 | -0.53 | 0.30 (0.07) |
| 3b | DRS | Expert | Large | Peek | Non-Ophth | Phone | 100 | -0.07 | 0.24 | -0.38 | 0.19 (0.06) |
| 4a | Peek | Expert | Large | Peek | Ophth | Phone | 100 | -0.08 | -0.11 | -0.56 | 0.35 (0.07) |
| 4b | Peek | Expert | Large | Peek | Non-Ophth | Phone | 100 | -0.06 | 0.21 | -0.33 | 0.25 (0.06) |
| 5 | DRS | Expert | Large | Peek | Expert | Large | 2,152 | 0.02 | 0.17 | -0.21 | 0.69 (0.01) |
| 6a | DRS | Expert | Large | Peek (Exp.Exam) | Expert | Large | 1,239 | -0.02 | 0.17 | -0.20 | 0.68 (0.02) |
| 6b | DRS | Expert | Large | Peek (Lay Exam) | Expert | Large | 913 | -0.02 | 0.16 | -0.21 | 0.71 (0.02) |
Note: DRS = reference desktop camera image. Peek = smartphone image. Expert = independent trained grader/image reader. Phone = smartphone on-screen disc grading application. Ophth = App grading performed by ophthalmologist. Non-Ophth = App grading performed by non health care worker.