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Proceedings Paper

Dynamic observing tonometry (DOT)
Author(s): Hartmut E. Kanngiesser; Yves C.A. Robert
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Paper Abstract

To help improve early detection of vascular eye diseases, a method, named Dynamic Observing Tonometry (DOT), for measuring the intra-ocular pressure (IOP) has been developed, which allows for simultaneous ophthalmoscopy and dynamic tonometry of the human eye. Material and Method. A system for the application of this method is presented, consisting of a transducer to be placed on the corneal surface and of a stand-alone base unit. The latter can be connected to a personal computer for further data processing and storage. The transducer consists of a Goldmann-type contact lens modified by implementing means for transparent pressure-measurement of IOP. A small flat membrane in the center of the lens applanates the cornea. A liquid transmits the applanation pressure from the opposite side of this membrane to a pressure sensor located outside the optical pathway. Time-dependent IOP's are transmitted telemetrically to the base unit for processing. Results. Current initial tests provide evidence for the viability of the concept and have demonstrated the performance of the system. Typical time dependent IOP measurements obtained with an experimental device are presented. Clinical trials with two prototypes are underway. Conclusion: The proposed device allows the ophthalmology to perform the ordinary slit-lamp fundus examinations combined with simultaneous dynamic tonometry. It offers for the first time easy and precise analysis of cardiac and respiratory- modulated intra-ocular pressure while directly observing the choroid and the papilla, as well as the analysis of heart rate variability and inspection of the iridocorneal angle at varying applied pressure. Moreover, dynamic observing tonometry gives easy access to examination procedures such as tonography and ophthalmodynamometry, which have been rarely performed despite their potential diagnostic value due to the complexity of experimental protocols hitherto used.

Paper Details

Date Published: 18 June 1999
PDF: 7 pages
Proc. SPIE 3591, Ophthalmic Technologies IX, (18 June 1999); doi: 10.1117/12.350570
Show Author Affiliations
Hartmut E. Kanngiesser, Ophthalmic Development Co. AG (Switzerland)
Yves C.A. Robert, Univ. Hospital/Univ. of Zurich (Switzerland)

Published in SPIE Proceedings Vol. 3591:
Ophthalmic Technologies IX
Bruce E. Stuck; Pascal O. Rol; Michael Belkin; Karen Margaret Joos; Fabrice Manns; Bruce E. Stuck; Michael Belkin, Editor(s)

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