Applanation tonometer having cornea alignment means

摘要

An applanation tonometer is disclosed for providing a measurement of intraocular fluid pressure inside the eye of a patient. The applanation tonometer includes a light-transmitting prism having a cornea contact tip at one end and a cornea alignment aid at the opposite end. The cornea alignment aid enables the patient to advise a vision professional when a light source of the tonometer is properly aligned with his cornea so that intraocular fluid pressure can be accurately measured. A light-blocking baffle is located at the opposite end of the prism, and a thin light-transmitting channel is formed through the baffle to lie on the longitudinal axis of the prism. In a preferred embodiment, the light baffle is at least one opaque disk, and the light-transmitting channel is a clear spot at the center of the opaque disk through which light is transmitted to the patient's cornea.

主权项

1. An applanation tonometer to measure an intraocular pressure of an eye of a patient undergoing testing, said applanation tonometer comprising:
a light source to generate light, said light source to be aligned with a cornea of the patient's eye undergoing testing; a light-transmitting body having first and opposite ends, a longitudinal axis running between said first and opposite ends, and a circular contact tip located at the first end to be moved into contact with an area of the eye undergoing testing and apply a pressure thereagainst, said circular contact tip being positioned to receive the light generated by said light source and transmitted in a first direction inwardly through said light-transmitting body towards the patient's eye and to reflect at least some of the inwardly-transmitted light in a second direction outwardly through said light-transmitting body away from the patient's eye depending upon the area of contact between the circular contact tip of said light-transmitting body and the patient's eye; a pair of circular light-blocking disks spaced one behind the other and embedded within the opposite end of said light-transmitting body, each of said pair of circular light-blocking disks having a diameter which is identical to one another and to the diameter of the circular contact tip of said light transmitting body and a light-transmitting channel running through a center thereof and lying along the longitudinal axis of said light-transmitting body so that the light that is generated by said light source is transmitted from said light source in said first direction through the light-transmitting channels of said pair of circular light-blocking disks located at the opposite end of said light-transmitting body to the circular contact tip located at the first end of said light-transmitting body by which the cornea of the eye undergoing testing is illuminated, such that the light with which the cornea is illuminated provides a visual indication to the patient whether said light source and the patient's cornea are aligned with one another to enable the intraocular pressure of the patient's eye to be measured; a photo detector to receive the light reflected by said circular contact tip in the second direction outwardly through said light-transmitting body and to provide an output signal in response thereto; and a force detector to provide an output signal in response to the pressure generated at the area of contact between the circular contact tip of said light-transmitting body and the patient's eye.