Artikel
Deviations between transpalpebral tonometry using TGDc01 and Goldmann applanation tonometry depending on the IOP level
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Autoren
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A. Troost
- Department of Ophthalmology, University of Mainz, Mainz
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K. Specht
- Department of Ophthalmology, University of Mainz, Mainz
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F. Krummenauer
- Department of Medical Biometry, Epidemiology and Informatics, University of Mainz, Mainz
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S. H. Yun
- Department of Ophthalmology, University of Mainz, Mainz
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N. Pfeiffer
- Department of Ophthalmology, University of Mainz, Mainz
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O. Schwenn
- Department of Ophthalmology, Bürgerhospital Frankfurt a. Main e.V., Frankfurt/Main
| Veröffentlicht: | 22. September 2004 |
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Gliederung
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Objective
Recent comparisons between transpalpebral tonometry using TGDc01 and Goldmann applanation tonometry were performed within normal populations with IOPs between 10 and 20 mmHg. The purpose of this study was to evaluate device deviations depending on patients' IOP levels.
Methods
A total of 68 eyes of 68 patients were included and assigned to 4 IOP levels according to an initial applanation tonometry assessment: level I: <10mmHg (n = 8), level II: 10-19mmHg (n = 20), level III: 20-29mmHg (n = 20), IV >30mmHg (n = 20). Two independent and randomized observers performed 3 replicate measurements per eye, respectively, observer 1 using TGDc01 tonometry and observer 2 using Goldmann applanation tonometry. Intraindividual deviations between measurement results were investigated concerning clinically relevance by comparison of medians and quartiles, concerning statistically significance by sign tests; p-values < 0.05 indicate local statistical significance.
Results
In patients with initial IOP > 20 mmHg TGDc01 based tonometry significantly underestimated the IOP as based on Goldmann applanation tonometry (p<0.001). This effect increased with increasing IOP: IOP level III median difference (TGDc01-Goldmann) -1,3 mmHg (interquartile range -2,5 ; -0,4), IOP level IV median difference -2,7 mmHg (-3,7 ; -1,0). In patients with initial IOP < 10 mmHg an at least gradual underestimation by TGDc01 tonometry (p=0.219) (median difference -0.6; -1.6 ; 0) was observed. In total 18% of patients showed device deviations > ±3 mmHg, and even 35% of patients among those with initial IOP >30mmHg.
Conclusions
TGDc01 based tonometry demonstrated an increasing underestimation of IOP with increasing IOP levels when compared to the goldstandard of Goldmann applanation tonometry.
