[Effect of tonometry on a glaucoma population study].

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.