Table 3.
Calculated VA demand across all schools (148 classrooms) and parameters used in calculation.
| Mean | Median | SD | Range | ||
|---|---|---|---|---|---|
| Min | Max | ||||
| Distance from board to closest seat (m) | 2.52 | 2.33 | 0.99 | 1.11 | 8.80 |
| Distance from board to furthest seat (m) | 6.63 | 6.75 | 1.92 | 2.10 | 11.50 |
| Average near working distance (cm) | 25.18 | 25.00 | 4.53 | 15.00 | 37.20 |
| Smallest letter height viewed at near (mm) | 1.50 | 1.50 | 0.50 | 1.00 | 3.00 |
| Smallest letter height viewed at far (mm) | 14.69 | 15.00 | 3.99 | 7.00 | 28.00 |
| VA demand at minimum distance (LogMAR) | 0.65 | 0.62 | 0.33 | 0.26 | 3.97 |
| VA demand at maximum distance (LogMAR) | 0.21 | 0.18 | 0.23 | − 0.13 | 2.20 |
| Near VA demand (LogMAR) | 0.60 | 0.60 | 0.17 | 0.14 | 1.00 |
| Actual near VA demand (LogMAR) | 0.20 | 0.21 | 1.70 | − 0.26 | 0.62 |
SD Standard deviation.