Fig. 1

Fig. 2

Values of IOP in mmHg measured by Schiotz and Tono-Pen Vet tonometers in healthy eyes of conscious dogs (31 dogs, 62 eyes)
| Animal no | Schiotz tonometer reading OD | Schiotz tonometer reading OS | Mean Schiotz tonometer reading | Tono-Pen Vet reading OD | Tono-Pen Vet reading OS | Mean Tono-Pen Vet reading |
|---|---|---|---|---|---|---|
| 1 | 16.0 | 20.0 | 18.0 | 15.0 | 18.0 | 16.5 |
| 2 | 15.0 | 16.0 | 15.5 | 17.0 | 18.0 | 17.5 |
| 3 | 16.0 | 16.0 | 16.0 | 20.0 | 20.0 | 20.0 |
| 4 | 19.0 | 16.0 | 17.5 | 17.0 | 15.0 | 16.0 |
| 5 | 24.0 | 22.0 | 23.0 | 22.0 | 23.0 | 22.5 |
| 6 | 19.0 | 18.0 | 18.5 | 14.0 | 12.0 | 13.0 |
| 7 | 16.0 | 17.0 | 16.5 | 13.0 | 11.0 | 12.0 |
| 8 | 18.0 | 17.0 | 17.5 | 18.0 | 19.0 | 18.5 |
| 9 | 16.0 | 18.0 | 17.0 | 24.0 | 21.0 | 22.5 |
| 10 | 18.0 | 17.0 | 17.5 | 22.0 | 22.0 | 22.0 |
| 11 | 19.0 | 16.0 | 17.5 | 20.0 | 23.0 | 21.5 |
| 12 | 21.0 | 18.0 | 19.5 | 22.0 | 19.0 | 20.5 |
| 13 | 14.0 | 14.0 | 14.0 | 23.0 | 21.0 | 22.0 |
| 14 | 16.0 | 18.0 | 17.0 | 19.0 | 18.0 | 18.5 |
| 15 | 12.0 | 13.0 | 12.5 | 25.0 | 22.0 | 23.5 |
| 16 | 14.0 | 17.0 | 15.5 | 17.0 | 17.0 | 17.0 |
| 17 | 16.0 | 14.0 | 15.0 | 17.0 | 15.0 | 16.0 |
| 18 | 18.0 | 17.0 | 17.5 | 21.0 | 22.0 | 21.5 |
| 19 | 18.0 | 16.0 | 17.0 | 17.0 | 16.0 | 16.5 |
| 20 | 12.0 | 16.0 | 14.0 | 18.0 | 16.0 | 17.0 |
| 21 | 16.0 | 20.0 | 18.0 | 16.0 | 13.0 | 14.5 |
| 22 | 18.0 | 16.0 | 17.0 | 17.0 | 18.0 | 17.5 |
| 23 | 16.0 | 17.0 | 16.5 | 22.0 | 21.0 | 21.5 |
| 24 | 14.0 | 13.0 | 13.5 | 12.0 | 11.0 | 11.5 |
| 25 | 12.0 | 14.0 | 13.0 | 16.0 | 16.0 | 16.0 |
| 26 | 18.0 | 16.0 | 17.0 | 16.0 | 12.0 | 14.0 |
| 27 | 15.0 | 16.0 | 15.5 | 11.0 | 13.0 | 12.0 |
| 28 | 16.0 | 15.0 | 15.5 | 24.0 | 22.0 | 23.0 |
| 29 | 13.0 | 14.0 | 13.5 | 23.0 | 23.0 | 23.0 |
| 30 | 14.0 | 16.0 | 15.0 | 23.0 | 21.0 | 22.0 |
| 31 | 14.0 | 16.0 | 15.0 | 12.0 | 12.0 | 12.0 |
| Mean ± SD | 16.2 ± 2.7a | 16.4 ± 2.0a | 16.3 ± 2.1a | 18.5 ± 3.9b | 17.7 ± 3.9b | 18.1 ± 3.8b |
| Minimum | 12.0 | 13.0 | 12.5 | 11.0 | 11.0 | 11.5 |
| Maximum | 24.0 | 22.0 | 23.0 | 25.0 | 23.0 | 23.5 |