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The Imbert-Fick "law" was invented by Hans Goldmann (1899–1991) to give his newly marketed tonometer (with the help of the Haag-Streit Company) a quasi-scientific basis; it is mentioned in the ophthalmic and optometric literature, but not in any books of physics. According to Goldmann,[1] "The law states that the pressure in a sphere filled with liquid and surrounded by an infinitely thin membrane is measured by the counterpressure which just flattens the membrane." "The law presupposes that the membrane is without thickness and without rigidity...practically without any extensibility."
The problem is that a sphere formed by such a membrane and filled with incompressible liquid (water) cannot be indented or applanated even when the pressure inside is zero, because a sphere contains the maximum volume with the minimum surface area.[2][3] Any deformation necessarily increases surface area, which is impossible if the membrane is inelastic, such as aluminum foil.
The law assumes that the cornea is infinitely thin, perfectly elastic, and perfectly flexible.[4] None of these assumptions are true. The cornea is a membrane that has thickness and offers resistance when pressed.i feel like ive been cheated.