# US 5,349,955 A · Tonometer

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- Number: US 5,349,955 A
- Document ID: US5349955A
- Status: Granted
- Kind: A
- Application number: 08/088,182
- Filed: 1993-07-06
- Granted: 1994-09-27
- Earliest claimed: 1992-07-27
- Assignees: Kowa Company, Ltd.
- Inventors: Takayoshi Suzuki
- Web page: https://patentgrep.com/patent/US5349955A

## CPC

- A61B 3/16: for measuring intraocular pressure, e.g. tonometers
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A tonometer is adapted to measure intraocular pressure by applying pressure onto of an eye being examined via its eyelid. The tonometer is provided with a pressure means that presses against the eyelid of a subject eye to thereby apply pressure to the eye. The load applied to the pressure means is detected by a Load sensor and used to calculate intraocular pressure of the eye. The tonometer with this arrangement is structurally simple and compact, operationally safe, and does not cause the patient to feel fear and discomfort.

## Claims

### Claim 1

A tonometer for measuring intraocular pressure by applying pressure onto an eye of a person being examined, comprising:
pressure means for pressing against an eyelid of an eye of a person being examined to thereby apply pressure to the eye;
drive means for driving the pressure means against the eye to cause the pressure means to apply pressure to the eye;
load sensor means for detecting a load applied to the pressure means;
calculating means for calculating intraocular pressure of the eye based on the load detected by the load sensor means when the pressure means presses on the eye; and
means for immobilizing the eye during the application of pressure thereto by the pressure means.

### Claim 2 (depends on 1)

A tonometer as set forth in claim 1, in which the drive means comprises a resilient member.

### Claim 3 (depends on 1)

A tonometer as set forth in claim 1, wherein the means for immobilizing comprises a cylinder movable into contact with the eye to immobilize the eye in a longitudinal direction by pressing against the peripheral portion of the eye via the eyelid thereof.

### Claim 4

A tonometric system for measuring intraocular pressure by applying pressure onto an eye of a person being examined, comprising:
pressure means for pressing against an eyelid of an eye of a person being examined to thereby apply pressure to the eye;
drive means for driving the pressure means against the eye to cause the pressure means to apply pressure to the eye;
load sensor means for detecting a load applied to the pressure means;
calculating means for calculating intraocular pressure of the eye based on the load detected by the load sensor means when the pressure means presses on the eye; and
an eye fixation lamp adapted to be disposed to fix the vision of the person's other eye to the front when intraocular pressure is being measured.

### Claim 5

A tonometer for measuring intraocular pressure by applying pressure onto an eye of a person being examined, comprising:
pressure means for pressing against an eyelid of an eye of a person being examined to thereby apply pressure to the eye;
drive means for driving the pressure means at a constant velocity against the eye to cause the pressure means to apply pressure to the eye;
load sensor means for detecting a load applied to the pressure means; and
calculating means for calculating intraocular pressure of the eye on the basis of changes over time in the load as detected by the load sensor means.