Indentation tonometers of the Schiotz type have been known for years and have been developed in various ways. Much knowledge is available on the foot plate, the plunger, relative movements and measurement values, plunger weights, and other information. Indentation tonometers have also been made with transducers to transform the movement of the plunger relative to the foot plate into an electrical signal that is processed electronically to produce a digital display and to record values. Prior art indentation tonometers of the mechanical variety suffer from inaccuracies, operator error, and critical manufacturing tolerances; and prior art indentation tonometers of the electrical variety having a digital readout suffer from complexity, large size, expense, and inconvenient operation.
This invention involves recognition of the problems of prior art indentation tonometers and proposes a simple way of making an automatic, digital reading instrument that is small, convenient, accurate, inexpensive, and self-contained within a hand holdable housing. The invention also aims at reliability, compatibility with existing parameters in the indentation tonometry art, and ease of cleaning and adapting the instrument to different measurements.