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| Optotype Size | LogMAR | Snellen |
| F1 | 0.70 | 20/100 |
| F2 | 1.00 | 20/200 |
| F3 | 1.30 | 20/400 |
| F4 | 1.60 | 20/800 |
| F5 | 1.90 | 20/1600 |
Snellen and equivalent LogMAR visual acuity values of the optotype sizes used in the Primary experiment.
