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Abstract
A study has been made of the relationship between the volume of fluid infused into the living and dead eyes of individual rabbits and the intraocular pressure. To minimize loss of fluid from the eye during the experimental procedure the infusion was made either at 197 µl min-1 or by a very rapid injection procedure. In individual rabbits the pressure/infusion volume relationship was found to differ significantly between the living and dead eye. In the dead eye the coefficient of ocular rigidity toas found to be approximately constant for pressures of 30 to 60 mm. Hg and to decrease below and above these pressures. In the living eye the coefficient of ocular rigidity was found to be at a maximum at a pressure of 25 to 30 mm. Hg and to decrease at pressures below and above this value provided the blood pressure was not exceeded. When the intraocular pressure exceeded the blood pressure the coefficient increased and approximated closely the value found in the dead eye at similar pressures. The marked influence of the blood supply to the eye on the pressure/infusion volume of the living eye has been demonstrated in experiments in ivhich either the general blood pressure was varied or the local blood supply to the eye teas decreased. The physiologic and practical significance of the results are discussed. It is emphasized that the volume of fluid injected into the living eye is not equal to the volume change of the eye. Thus, it is quite unjustifiable to utilize this type of relationship in tonographic measurements of the intraocular dynamics.