The Elastic Properties of the Human Eye

Introduction  The rigidity of the eye as defined by the equation of Friedenwald has been shown to vary in the rabbit¹ and cat² with changes of the intraocular pressure (IOP). These observations are of interest because they might apply to the human eye and be relevant to the tonographic measurement of facility of outflow. In tonography, as presently practiced, it is presumed that the "rigidity" of the eye does not vary at different pressure levels, and calculations for facility of outflow are made on this basis. It thus becomes important to determine whether the human eye behaves as the eye of the cat and rabbit or whether it indeed has a constant coefficient of rigidity, as supposed by Friedenwald.³

Methods  Nine human eyes were examined in this study. Six of these eyes (Eyes 1 to 6) were received from the Buffalo Eye Bank, stored in refrigerated isotonic