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US 5,148,807 AGranted
Non-contact tonometer
AssigneeThe Ohio State University
InventorHsiung Hsu
Life of this patent
Estimating the term…
Abstract
A non-contact, non-invasive tonometer utilizing the technique of angle modulation of high frequency sound waves or high frequency light waves to determine the intraocular pressure of an eye. The angle modulation technique can be either frequency modulation or phase modulation.
Claims15
A tonometer for use in the non-contact measurement of intraocular pressure of an eye comprising, in combination:
- means for producing a low frequency perturbating acoustic wave adapted to be positioned proximate a fixed eye wherein such perturbating acoustic wave is directed toward the eye for causing a vibration on the surface of the eye, the intensity of the vibration being dependent upon the intraocular pressure;
- means for transmitting a high frequency wave adapted to be positioned proximate said perturbating wave producing means and the eye, such high frequency wave being transmitted toward the eye for reflection off the perturbated surface of the eye;
- means for receiving such reflected high frequency wave and for detecting any modulation in the phase angle of such high frequency wave created by the acoustic vibration of the surface of the eye;
- means for creating an output signal based upon such phase angle modulation;
- and
- means for displaying such output signal for viewing.
3 more elements
A tonometer for use in the non-contact measurement of intraocular pressure of an eye comprising, in combination:
- means for producing a low frequency perturbating acoustic wave adapted to be positioned proximate a fixed eye wherein such perturbating acoustic wave is directed toward the eye for causing a vibration on the surface of the eye, the intensity of the vibration being dependent upon the intraocular pressure;
- means for transmitting a high frequency wave adapted to be positioned proximate said perturbating wave producing means and the eye, such high frequency wave being transmitted toward the eye for reflection off the perturbated surface of the eye;
- means for receiving such reflected high frequency wave and detecting any modulation in the frequency of such high frequency wave created by the acoustic vibration of the surface of such eye;
- means for creating an output signal based upon such modulation;
- and
- means for displaying such signal for viewing.
3 more elements
A tonometer for use in the non-contact measurement of intraocular pressure of an eye comprising, in combination:
- means for producing a low frequency perturbating acoustic wave adapted to be positioned proximate a fixed eye wherein such perturbating acoustic wave is directed toward the eye for causing a vibration on the surface of the eye, the intensity of the vibration being dependent upon the intraocular pressure;
- means for transmitting a light wave adapted to be positioned proximate said perturbating wave producing means and such eye;
- wave splitting means for receiving such transmitted light wave and producing therefrom a first light wave and a second light wave of equal phase;
- means for transmitting such first light wave toward the eye for reflection off such perturbated surface of the eye, such first light wave developing a variable phase delay dependent upon the vibration of the surface of the eye;
- means for transmitting such second light wave having a fixed phase delay to a light detecting means;
- said light detecting means also receiving such reflected first light wave from such perturbated surface of the eye, such first and second light waves being merged at said light detecting means wherein the variation in phase delay between such first and second light waves will produce a moving fringe interference pattern;
- means for processing such moving fringe interference pattern and creating an output signal;
- and
- means for displaying such output signal for viewing.
6 more elements
Dependencies are inferred from the claim text.