Patent ID: 7479109

Claim:
A system ensuring replacement of a molded resin cornea contactor used in an eye examining instrument having a microprocessor and a holder for receiving the cornea contactor in an operating position, the system comprising: the cornea contactor being molded to have an element that is deformable in a direction of insertion of the cornea contactor into the holder; a strain gauge arranged in the holder to engage the element as the cornea contactor is being inserted into the holder and before the cornea contactor reaches the operating position; the strain gauge being arranged to deform the element from its initial position to a deformed position as the cornea contactor is moved fully into the holder to the operating position; the strain gauge being arranged to produce a strain signal delivered to the microprocessor representing the strain involved in deforming the element from its initial position to its deformed position; the element being configured so that a first deformation of the element from its initial position to its deformed position requires more stress than any subsequent deformation of the element from its initial position to its deformed position; the microprocessor being programmed to distinguish between a strain signal from the strain gauge representing the first deformation of the element and a strain signal from the strain gauge representing the subsequent deformation of the element; and the microprocessor being programmed to proceed with an eye examination only if a cornea contactor inserted into the holder causes the strain gauge to produce a strain signal representing the first deformation of the element.