51 results about "Applanation tonometer" patented technology

A portable non-contact tonometer (2) for measuring Intra-Ocular Pressure (IOP) of subject's eye is presented. Tonometer (2) is designed to be operated by the subject himself. It is housed in a hand-held case (4) which contains compressed air source (40), eye alignment detectors (12, 14), cornea applanation detector system (8, 10), a pressure sensor (32) and optical system for presenting gaze target (48). The animated gaze target (48) advantageously draws subject's attention to itself and keeps his eye (62) in alignment long enough for the measurement to take place, while optionally displaying system status and operating instructions. An audio annunciation system (16) guides the subject in the operation of the tonometer and prepares him for the actual procedure. The timing of the air puff is randomized to prevent subject's conditioning. The overall operation of the tonometer is controlled by a built-in microprocessor (50) system. A 3-D map of cornea is computed and a technique to compute the IOP derived from the difference of 3-D corneal maps before and during the air puff application is disclosed.

A tonometer (10), for determining intraocular pressure, has a body, which can be a transparent, substantially tubular body (12). A plunger (28) is located within the body and a coil spring (36) acts between the body and the plunger. A marker (24) member is frictionally retained within the body and is displaced relative to an external scale (20) on the body. In use, the tonometer is brought up against the eyelid (50) of a closed eye and the body displaced relative to the head of the plunger, until the pressure is sufficient to create a pressure phosphene. The device is then removed and the displacement of the marker member, indicative of the applied pressure is read. This reading corresponds to the intraocular pressure. The device may include a return member (49) for returning the marker member to a zero or rest position. <IMAGE>

An excessive amount of pressurized air is inhibited from being blown to an eye of a patient during measurement of a corneal shape deformation amount. In a non-contact tonometer having a piston, a driving unit to drive the piston, a fluid ejection unit to blow air pressurized by driving the piston toward a cornea of an eye to be inspected, and an intraocular pressure measuring unit to detect a deformed state of the cornea and measure an intraocular pressure, there are provided a piston displacement restricting unit that restricts a displacement amount when the piston pressurizes the air, and a changing unit to change the displacement amount to be restricted by the piston displacement restricting unit.

A tool for calibrating a non-contact tonometer (NCT) comprises a body having a mating feature configured for removably mounting the body on the nosepiece or on the measurement head of the NCT, a pressure sensor carried by the body and arranged to receive an air pulse discharged by the NCT to provide a pressure signal in response to the air pulse, and a radiation emitter carried by the body, wherein the radiation emitter provides a pseudo-applanation event when the pressure signal reaches a predetermined level that is detectable by the NCT as though an actual corneal applanation had taken place. In one embodiment, the mating feature includes a mounting orifice for receiving a portion of the nosepiece. In another embodiment, the mating feature includes a pair of mounting pins sized for receipt by a corresponding pair of mounting holes in the measurement head of the NCT.

The invention relates to a contact applanation tonometer. The contact tonometer comprises a probe, a light source, a first image sensor, a convex lens, a strain gauge, a microprocessor and a display memory. The probe is in a circular truncated cone shape with small bottom and large top, and is made from a transparent optical material; an inclined plane is arranged at the lateral surface of the probe; the width d of the inclined plane is 3-10 millimeters; an elastic beam is fixedly installed at the upper end of the probe; the external end of the elastic beam is fixedly connected with the lower end of a housing; the strain gauge is installed on the elastic beam; the light beams emitted by the light source are perpendicularly incident to the upper end of the probe after being collimated to be parallel beams by the convex lens; and after sequentially going through the total reflection on the lateral surface and the lower bottom surface of the probe, and the reflection on the inclined plane of the probe, the light beams directly enter the first image sensor. The contact tonometer can continuously and dynamically detect multiple intraocular tension values during measurement of the intraocular tension.