[Measurement of ophthalmic blood pressure with the Mikuni dynamometer (author's transl)]

Comparative measurements of the ophthalmic arterial blood pressure (Mikuni ophthalmodynamometer) and the systemic blood pressure (Riva-Rocci sphygmomanometer) were carried out in 141 eyes of healthy subjects. There was a linear correlation between the two parameters (p < 0.001). The mean diastolic ophthalmic blood pressure was 58.6 mmHg, the mean systolic blood pressure of 93.4 mmHg. The mean diastolic brachial arterial pressure was 86.7 mmHg, the mean systolic pressure 136 mmHg. In all eyes studied the ophthalmic blood pressure was lower than the ipsilateral brachial blood pressure, in respect of the diastolic as well as of the systolic pressure. On the average the ophthalmic blood pressure was 70% of the systemic blood pressure (mean difference 33.6 mmHg). There was no statistically different regression line between the two parameters in subjects with normal and subjects with elevated systemic blood pressure. In 86% of the paired measurements with the Mikuni ophthalmodynamometer there were differences of less than 5 mmHg in systolic pressure (mean 2.64 mmHg). Correspondingly all differences in diastolic pressure in paired measurements were within 5 mmHg (mean 1.46 mmHg). A difference of 7 mmHg in ophthalmic arterial pressures in an individual appears to be probably pathologic; a difference of more than 9 mmHg seems to be definitely pathologic. In ophthalmodynamometry using the Mikuni instrument a "tonographic effect" occurs, and the intraocular pressure takes 10-15 minutes to return to a physiologically stable state. The extent of this tonographic effect depends on the IOP prior to dynamometry. (p < 0,05).