Applanation tonometer having cornea alignment means

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.