Mean (SD) time interval from HRT1 to HRT2 and mean (SD) ages of subject groups
| Normal subjects | Converters | OHT | |
| Mean (SD) time from HRT1 to HRT2 (months) | 21.5 (8.5) | 16.3 (8.5) | 16.6 (9.7) |
| Mean (SD) age (years) | 65.1 (10.1) | 67.9 (8.9) | 63.3 (9.4) |
HRT = Heidelberg retina tomograph; OHT = ocular hypertensive.