Ophthalmic pulse studies. I. Influence of intraocular pressure.

The relationship of the ophthalmic pulse amplitude to the intraocular pressure has been described in rabbits and dogs. The effect of a suction cup on the intraocular pressure has been investigated in rabbit eyes and human eyes. Sample pulse tracings have been obtained using a suction cup on rabbits and man. Two estimates were made of the volume changes associated with the ophthalmic pulse xoave: (1) by using the pressure variation and ocular compliance, (2) by direct measurement toith a mercury strain gauge. An analogue model, dependent only on mechanical properties of the eye and ocular blood vessels, has been described which gives an approximate reproduction of the pulse amplitude versus intraocular pressure curve. In any study correlating pulse amplitude with a disease process, the intraocular pressure at the time of measurement must be considered. Comparisons of the ophthalmic pulse in two eyes can actually be done only at the same intraocular pressure. Increased pulse amplitude in glaucoma can be explained by the response of the pulse amplitude to the intraocular pressure.