Ophthalmodynamometry has now been practiced for some 50 years, and the method is in general use for the diagnosis of carotid occlusion, but it has never been clearly established what relation the readings of the instrument bear to true retinal artery pressure. Calibration curves have been offered for Bailliart's instrument, based on measurement of intraocular pressure by tonometry while the dynamometer is applied to the sclera.1 These results were obtained on anesthetized cats, and their reliability has been strongly criticized by Duke-Elder,2 but no substitute has been offered. In the absence of reliable calibration curves, it is not profitable to compare retinal artery and brachial artery pressure, and most observers today are content to record retinal artery pressure in grams of applied pressure, without attempting the conversion to millimeters Hg.
The instrument commonly used is the Bailliart's model. This is available in 2 designs, but the shape of
LOWE RD. Calibration of Bailliart's Ophthalmodynamometer. Arch Ophthalmol. 1962;67(4):424-427. doi:10.1001/archopht.1962.00960020426008