COMPARATIVE INTRAOCULAR-PRESSURE MEASUREMENTS WITH POSITION INDEPENDENT HAND-APPLANATION TONOMETERS

A study of comparative intraocular pressure [IOP] measurements was made using the hand-held applanation tonometers of Perkins and Draeger in the sitting and lying patient. A series of 100 patients was investigated by 2 observers taking the pressures with both tonometers under blind conditions. The statistical evaluation of the data revealed an average IOP increment when lying down of 2.5-3 mm Hg for both observers and both tonometers. This postural response was fully reversible when getting up and a statistically significant overshoot-phenomenon was noted. The pressure increment when lying down was not related to initial IOP level and there was no clear relationship to the age of the patients tested. Interobserver variation and variations of both tonometers were evaluated. The effect of repeated tonometry was considered. Some aspects of position influence on IOP were discussed.