A new method of simultaneously measuring the applanation force and area as applied to tonometer prototype

Xueyong Zhang; Jianguo Ma

doi:10.1117/12.716283

25 October 2006 A new method of simultaneously measuring the applanation force and area as applied to tonometer prototype

Xueyong Zhang, Jianguo Ma

Author Affiliations +

Proceedings Volume 6280, Third International Symposium on Precision Mechanical Measurements; 62802M (2006) https://doi.org/10.1117/12.716283
Event: Third International Symposium on Precision Mechanical Measurements, 2006, Urumqi, China

Abstract

A new method for simultaneous measuring the applanation force and area and a device based on this method are presented for intraocular pressure measurement. A photoelectric probe transducer acting as applalation area detector converted the diminished quantity of light returned from applanation surface of the cone prism into one electronic signal, and a micro strain gauge acting as applation force detector converted changing load related to the resilient force of the eye into another electronic signal. A 16-bit single-chip microprocessor with E²PROM in the electronic circuit played the role of a nucleus, which stored the program instructions and the interrelated data. Laboratory experiments were carried out on a stimulated cornea clamped in a Perspex chamber connected to a hydraulic manometer to obtain intraocular pressure at different levels. Preliminary trials were carried out comparing the values obtained with those of the Goldmann tonometer. Diminished quantity of the light is directly proportional to the applanation area of the cornea and the changing load detected by strain gauge is equated to the resilient force of the eye. A new kind of tonometer can be constructed based on this principle. Experimental results on a stimulated eyeball showed the present tonometer reading has good agreement with that of the Goldmann tonometer. Further study including clinical trials and application is required to evaluate the accuracy and usefulness of this method.

Citation Download Citation

Xueyong Zhang and Jianguo Ma "A new method of simultaneously measuring the applanation force and area as applied to tonometer prototype", Proc. SPIE 6280, Third International Symposium on Precision Mechanical Measurements, 62802M (25 October 2006); https://doi.org/10.1117/12.716283

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