Fundamental principals and applied biophysics

Summary Pascal tonometry is a pressure sensor, made by a piezoresistive mycrocristal mounted on a concave tonometer, thus allowing a minimal contact with the anterior surface of the cornea. This design is meant to minimize the impact of the corneal components in the measurement of the transmural pressure. Carrying a weight of approximately 1 g, the tonometer itself has 7 mm in diameter with the crystal occupying the central 1.2 mm. Its 100 Hz reading rate allows a continuous pressure measurement which can be influenced by a number of variables ranging from axial length, to corneal elasticity.