Purpose: The purpose of this study was to evaluate the influence of tonometry in detecting the occurrence of glaucoma.
Methods: The subjects, 845 out of 3,488 residents aged 40 years or older, were examined according to standard protocols, including tonometry, slit lamp examination, fundus photography, and automatic perimetry as a recall examination. The intraocular pressure in each subject was measured by both Goldmann applanation tonometer(GAT) and noncontact tonometer CT-70 (NCT).
Results: The mean +/- standard deviation intraocular pressure measured by GAT was 15.52 +/- 2.57 mmHg, and 15.03 +/- 2.90 mmHg by NCT. There was a statistically significant correlation(p < 0.0001). The difference between pairs of measurements by GAT and NCT was 0.50 +/- 1.93 mmHg. There was no influence of tonometry in detecting the incidence of glaucoma, which was 4.14%; primary open-angle glaucoma 0.59%, normal tension glaucoma 2.6%, primary angle-closure glaucoma 0.47%, and other types of glaucoma 0.48%. The detection of ocular hypertension was different, and was 2.13% with GAT and 2.72% with NCT.
Conclusion: In our study, the influence of tonometry in detecting the incidence of glaucoma was very small. A noncontact tonometer is considered to be useful for glaucoma population study.