Noninvasive tonometry of intraocular pressure over a closed eyelid

• Autorzy: Nakai M. , Yoshizawa I. , Fujita A. , Takeda S. , Yanasima K. , Uchiyama A. , Yanagisawa M.
• Języki publikacji: EN

Abstrakty

EN

For more than 40 years, methods to measure intraocular pressure over a closed eyelid have been studied but without much success. The eyelid thickness varies among individuals, and this has been a major obstacle. This report presents our findings that vibrating the eyeball with an activator evokes a response depending on ocular pressure changes. The eyeball is vibrated with a ceramic transducer over the closed eyelid, and the value of the current flowing through the transducer is measured. The acoustic load of the transducer varies when it comes in contact with the object in which the internal pressure changes. As a result, the electrical impedance, in turn, varies in response to this load. Consequently, the current varies when an alternating voltage is applied to the transducer. Thus, intraocular pressure is converted from current value. A device based on this phenomenon was developed. It measures intraocular pressure within seconds, after being placed on the closed eyelid, and its weight is less than 55 g. The device was tested on 10 human eyes. The correlation coefficient in between our tonometer and the model routinely used in clinical use was about 0.93. Therefore, the new method is sufficiently accurate for clinical application.

Słowa kluczowe

EN

intraocular pressure; noninvasive tonometry; biomeasurement

PL

ciśnienie wewnątrzgałkowe; tonometria nieinwazyjna; biopomiar

• Wydawca: Nałęcz Institute of Biocybernetics and Biomedical Engineering of the Polish Academy of Sciences ; Elsevier
• Czasopismo: Biocybernetics and Biomedical Engineering
• Rocznik: 2007
• Tom: Vol. 27, no. 1-2
• Strony: 199--205
• Opis fizyczny: Bibliogr. 8 poz., rys., wykr.

Twórcy

autor

Nakai M.

autor

Yoshizawa I.

autor

Fujita A.

autor

Takeda S.

autor

Yanasima K.

autor

Uchiyama A.

autor

Yanagisawa M.

• T152-0003, 14-10, 4-chome, Himonya, Meguro-ku, Tokyo, Japan,

Bibliografia

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• 5. Hill R.A.: New Applications for Pulsed and CW lasers in Treatment of Glaucoma, Lasers and Electro-Optics Society Annual Meeting, LEGS '92, Conference Proceedings, 1992, 658-659.
• 6. Asrani S., Zeimer R., Wilensky J.: Large diurnal fluctuations in intraocular pressure are in independent risk factor in patients with glaucoma, Journal Glaucoma, 2000, 2, 339-347.
• 7. Marchetto P.: Error Measurement for a Portable Tonometer, Bioengineering Conference, 2002, Proceedings of the IEEE 28th Annual Northeast, 2002, 85-86.
• 8. Machay R.S., Marg E.: Fast automatic electronic tonometers based on exact theory, Acta Ophthalmol., 1959, 46, 495-507.