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Abstract #18474 Published in IGR 3-3
Clinical comparison of two intraocular pressure measurement methods: SmartLens dynamic observing tonography versus Goldmann
Troost R; Vogel A; Beck S; Schwenn O; Grus F; Pfeiffer NGraefe's Archive for Clinical and Experimental Ophthalmology 2001; 239: 889-892
PURPOSE: To compare intraocular pressure (IOP) measurements obtained with SmartLens, a gonioscopic contact lens, to those with Goldmann applanation tonometry. METHODS: Eighty volunteers (20 healthy individuals and 60 glaucoma patients from the University Eye Hospital's outpatient department) were examined using conventional Goldmann tonometry and the new SmartLens tool. For each device, three replicate measurements were performed. A paired t test and the corresponding mean difference confidence interval approach were used to assess deviations in location of the two tonometric methods; the test procedure of Maloney and Rastogi was used for comparison of precision in paired data. Intraindividual differences were evaluated according to the approach of Altman and Bland. RESULTS: There was a mean difference of 5.6 mmHg (95% CI: 4.3 mmHg; 6.8 mmHg; p < 0.01) in IOP between the two methods, with a significant overestimation by SmartLens compared to Goldmann tonometry (p < 0.01). The 95% limits of agreement ranged from -5.4 mmHg to +16.6 mmHg for individual patients. The measurement method variance of SmartLens was higher (Maloney-Rastogi test; p < 0.01). The mean coefficients of variation for intraindividual replicates were 10.1% (SmartLens) and 3.8% (Goldmann) (p < 0.01). CONCLUSIONS: Accepting Goldmann tonometry as the gold standard for IOP measurement, the SmartLens method showed considerable variation and, therefore, was not proven to be an adequate substitute for Goldmann tonometry.
Dr R. Troost, Coordination Centre for Clinical Trials, University of Mainz, Obere Zahlbacher Strasse 69, 55131 Mainz, Germany. troost@imsd.uni-mainz.de
Classification:
6.1 Intraocular pressure measurement; factors affecting IOP (Part of: 6 Clinical examination methods)