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Abstract
Blood flow velocity in the ciliary body was measured with a specially designed, miniature Doppler flow detector. The transducer consisted of two crystals mounted in a groove of a metal disk, 8 mm. in diameter and 3.5 mm. thick ivith an efficient area of 2 by 3 mm. Blood velocity in the ciliary body at various intraocular pressures was investigated in 18 anesthetized albino rabbits. The relationship between perfusion pressure (arterial pressure minus intraocular pressure) and blood velocity in the ciliary body gave a sigmoid, curve. This relation re-plotted on probability paper was linear, fitting well to an integration of a binominal curve. When the Doppler shift was plotted against the intraocular pressure instead of the perfusion pressure, similar results were obtained. In order to represent the sigmoid curve, the intraocular pressure when df/dp was maximum, was calculated (Pm); where f is the relative Doppler shift and P is the intraocular pressure. A linear relation was found, between systemic arterial blood pressure (Pb) and Pm, giving a regression equation of Pm = 0.60Pb - 9.15. No reactive hyperemia was found in the ciliary body vessels of rabbits after a release of elevation of intraocular pressure.