13 June 2002 Design and realization of a handheld vibrometer system for noncontact in-vivo detection of microvibrations of the human eye to determine the intraocular pressure (IOP)
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Proceedings Volume 4611, Ophthalmic Technologies XII; (2002); doi: 10.1117/12.470585
Event: International Symposium on Biomedical Optics, 2002, San Jose, CA, United States
Abstract
To allow measurements of the intraocular pressure (IOP) by glaucoma patients themselves (self-tonometry) a handheld-interferometer system for non-contact in vivo measurements of microvibrations of the human eye was realized. The measurement principle is based on the dependence of the resonance frequencies of the human eye on the IOP. To analyze this, the human eye is stimulated by ultrasonic waves and the induced microvibrations are measured with a vibrometer and processed by a DSP unit. Beside a stabilized diode laser and a low noise photodetector an exact three-dimensional positioning system had to be developed to guarantee reliable measurements. To investigate the corresponding requirements a camera-based system for the detection of human eye movements was developed and test series with several persons were made. Based on these results an adjustment unit was integrated in a miniaturized interferometer system: After a short self-adjusting procedure lateral to the setup by overlaying two targets of a highly sensitive optical system the correct measuring distance between the cornea and the vibrometer parallel to the optical axis is determined automatically by an astigmatic auto-focus system. With this handheld-vibrometer in vivo measurements with several test persons were made with very good results concerning the reliability and handling capability.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Arnd Gundlach, Rainer Rawer, Stefan Hey, Wilhelm Stork, Klaus-Dieter Mueller-Glaser, "Design and realization of a handheld vibrometer system for noncontact in-vivo detection of microvibrations of the human eye to determine the intraocular pressure (IOP)", Proc. SPIE 4611, Ophthalmic Technologies XII, (13 June 2002); doi: 10.1117/12.470585; https://doi.org/10.1117/12.470585
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KEYWORDS
Eye

Cornea

In vivo imaging

Interferometry

Digital signal processing

Cameras

Interferometers

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