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Ultrasound biomicroscopy showed that filtering bleb formation was frequent in eyes having DS with RHAI but that it was not the only surgically induced IOP-lowering mechanism. Increased uveoscleral and transscleral filtration may be equally important.

Purpose: To provide data on the prevalence of ocular hypertension and glaucoma and on the diagnostic validity of tonometry. Methods: In this cross-sectional, population-based study, 4,927 subjects over 40 years of age were examined. Each subject underwent a complete ocular examination as part of the Egna-Neumarkt Glaucoma Study. These examinations were carried out by trained, quality-controlled ophthalmologists, according to a predetermined standard protocol that included a medical interview, applanation tonometry, computerized perimetry, optic nerve head examination and other ocular measurements. The following data were recorded: mean IOP, prevalence of ocular hypertension, primary open-angle glaucoma and normal tension glaucoma. Sensitivity, specificity and the predictive value of the tonometric test, as well as the distribution of IOP in the different groups were also determined. Results: The overall prevalence of ocular hypertension, hypertensive primary open-angle glaucoma and normal tension glaucoma corresponded to 2.1, 1.4 and 0.6%, respectively. Other types of glaucoma accounted for a further 0.9%. The sensitivity and specificity of the tonometric test in recognizing glaucoma (cut-off between 21 and 22 mm Hg) were, respectively, 80.1 and 97.8%. The predictive values of the positivity and negativity of the test were 52.1 and 99.4%, respectively. Conclusions: The prevalence of ocular hypertension and glaucoma was similar to that found in several recent epidemiological studies. Tonometry alone is obviously not sufficient to ascertain or to exclude the presence of glaucoma; its diagnostic validity however is high and should never be underestimated. An elevated IOP is the main risk factor for glaucoma, with the degree of risk increasing as the level of IOP increases.

Purpose To compare the measurements of intraocular pressure (IOP) with dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in healthy and glaucomatous eyes and to evaluate the influence of corneal thickness (CCT), corneal curvature (CC), axial length (AL), and age on these tonometric alternatives. Methods Three hundred eyes of 100 healthy subjects, 100 patients with primary open angle glaucoma, and 100 patients with primary angle-closure glaucoma underwent IOP evaluation with DCT and GAT, and measurements of CCT, CC, and AL. Bland-Altman plots were used to evaluate the agreement between tonometers. Regression analysis was used to evaluate the influence of ocular structural factors on IOP measurements obtained with both tonometers. Results Bland-Altman plots indicated that the 95% limits of agreement between tonometers were À1.4 to 6.6 mmHg. DCT values measured 2.6 ± 1.9 mmHg higher than GAT readings (Po0.001). The mean IOP difference between DCT and GAT (DIOP) was higher in healthy than in glaucomatous eyes and the magnitude of difference increased with increasing CCT. A significant reduction of DIOP with an increase in both CCT (Po0.001) and IOP values (Po0.001) was found. Regression analysis showed no effect of CC, AL, and age on both DCT and GAT readings. In contrast to GAT (Po0.001), DCT measurements were not influenced by CCT (P ¼ 0.43).Conclusions IOP readings obtained by DCT were higher and less affected by CCT than those by GAT. The DIOP was higher in healthy than in glaucomatous eyes and decreased in relation to increased CCT and IOP values.