OODG-Ulrich and OPG-Gee: a comparative study.

For an adequate assessment of both the ophthalmological and the neurological consequences of carotid obstruction measurement of the blood pressure in the carotid flow area is essential. To this end there are two objective, registrating methods available at the moment: OPG-Gee and OODG-Ulrich. A comparative study was made into the basic principles, calibration curves and application methods of these systems. By both methods the systolic retinal--and ciliary--as well as the diastolic ocular blood pressure can be measured. OODG is more exact for the differentiation and measurement of the two systolic blood pressures. OPG-Gee, however, offers the unique additional possibility of a judgement on the systolic blood pressure in the carotid siphon without, however, taking into account a (difference in) pre-existing intraocular pressure. Our own investigation shows that in order to obtain a correct assessment of the carotico-brachial relation both blood pressures should be measured simultaneously. The results of the graphic analysis of the curves are compared to those by Ulrich. For the diagnosis of carotid obstructions this analysis of the shape had no advantages over the determination of the pressure values. Finally, a survey is given of possible applications of OPG and OODG in various other syndromes.