Purpose: To evaluate and compare the intraocular pressure measurement variability between Goldmann applanation tonometry (GAT), Pascal dynamic contour tonometry (DCT), and ocular response analyzer (ORA) tonometry.
Methods: Subjects were prospectively recruited from consecutive Albuquerque VA Medical Center eye clinic patients that were previously diagnosed with ocular hypertension, glaucoma suspect, primary open-angle, or normal pressure glaucoma. Two sets of intraocular pressure measurements (3-4 ORA, 2 DCT, and 2 GAT) were obtained approximately 15 minutes apart. Each set was obtained by 1 of 2 examiners using random examiner sequences. ORA was measured first in both eyes, followed by either DCT or GAT, which were obtained in random order. Repeatability was assessed by examining variability of consecutive measurements by the same examiner, and reproducibility was examined by assessing variability between the first and second measurement sets.
Results: One hundred and twenty eyes of 60 subjects were included. Mean age was 64.1+/-9.6 years and 58/60 (97%) were male. Intraobserver repeatability was highest for GAT, followed closely by DCT, and then ORA. Intersession reproducibility was similar for all methods, although a tonographic effect may have corrupted GAT and DCT reproducibility results. We found no repeatability or reproducibility differences between eyes, between examiners, or between measurement sets.
Conclusions: Although some intermethod variability differences were identified, all 3 methods in this study demonstrated clinically acceptable measurement repeatability and reproducibility. This result, in conjunction with the finding that variability was not different between eyes, examiners, or measurement sets, suggests that DCT and ORA are reliable enough to be clinically useful.