Studies in ocular rigidity

Abstract

(1) There is some evidence that rigidity varies in the individual eye. These variations could be due either to changes in the elastic properties of the coats of the eye or to alterations in the intra-ocular vascular bed. (2) Determinations of rigidity were carried out in vitro on corneo-scleral envelopes prepared from enucleated human eyes. The degree of hydration of the cornea and sclera was varied by bathing the tissues in solutions of different osmolarities; alterations in the water content were assessed by measurements of the thickness of the cornea and sclera. (3) Reduction of the water content of the cornea and sclera caused an increase in ocular rigidity, while hydration of the tissues had the opposite effect. Gross changes in thickness were necessary before any significant changes occurred in rigidity. (4) Water-drinking tests in a series of patients with suspected glaucoma gave negative results, and no consistent changes were found in ocular rigidity during the tests. (5) It is concluded that alterations in the physical properties of the coats of the eye are unlikely to be responsible for variations in rigidity in an individual eye.