Pneumatonographic studies on normal and glaucomatus eyes

Abstract

A new methodological approach, embodied in the pneumatonograph, has been used to study the intraocular pressure, intraocular pulse and aqueous humor dynamics of normal and glaucomatous eyes. Comparative measurements of intraocular pressure in seated subjects by the Goldmann instrument and the pneumatonograph indicate close agreement over a wide range of pressures. On changing from the sitting to the supine position, it has been found by pneumatonometry that there is a significant increase of intraocular pressure in all eyes. In glaucomatous eyes, this postural response ranged up to as high as 12 mm Hg. Comparison of Schiotz and pneumatonometric pressure measurements on supine patients showed that the Schoitz values are significantly lower. This discrepancy of the values is in keeping with recent studies indicative that the Schiotz calibration is in error by 3-6 mm Hg. The coefficient of outflow facility was measured by a procedure of applanation tonography employing pressure-volume relations for the living human eye. The range of values found for normal eyes was significantly different from those of glaucoma eyes. It is concluded that pneumatonography is a useful method for improving the effectiveness of glaucoma diagnosis and clinical management.