Abstract: A portion of the cornea or similar flexible membrane is flattened by urging against the cornea a footplate with a measurable force and deriving a signal proportional to the magnitude of the applanated area of the cornea when the applanating force is compared to a threshold which corresponds to a force equal to a selected reference force on the planar footplate contacting the cornea. When the selected reference force signal is reached the area of the applanated region of the cornea is transferred as a signal for scaling by another signal proportional to the force.

Abstract: A portion of the cornea or similar flexible membrane is flattened by urging against the cornea a footplate with a measurable force and the magnitude of the applanated area of the cornea is sensed and compared to a threshold which corresponds to an area equal to a selected reference area of the planar footplate contacting the cornea. When the selected threshold is reached the force urging the footplate against the cornea is processed for scaling by another signal proportional to the reference area. In another embodiment signals proportional to both the applied force and the applanated area are digitized for averaging and/or storage and the two parameter functional dependence of area on the force or a selected region thereof is displayed and recorded for analysis.