Vascular Distensibility in the Eye

Distensibility of the intraocular vascular bed was studied in the living cat eye by measuring the alterations of ciliary artery blood pressure and intraocular pressure induced by varying degrees of acute common carotid artery occlusion. A semilogarithmic relationship was found between alterations in ciliary artery blood pressure and ocular volume changes. The slope of this relationship, termed the "coefficient of vascular rigidity," was found to be approximately 1.5 times the ocular rigidity in all eyes tested. Similar values were obtained by direct perfusion of the ophthalmic artery in enucleated cat eyes when alterations in vascular perfusion pressure were induced from a baseline value of 50 mm Hg. The results indicate that measurements of intraocular volume changes after acute common carotid compression may offer a clinical method of determining vascular rigidity in the eye.