Comparison of vertical fixation disparities between essential hypertensives and matched normotensives.

Using American Optical Vectographs and a Disparometer, vertical fixation disparities and associated phorias were measured on 19 essential hypertensives and 19 matched normotensives. Subjects were matched on the basis of race, sex, age, use of tobacco, and family history of hypertension. Correlated variance comparisons of the measured associated phorias and fixation disparities, as well as calculated x and y intercepts derived from forced-duction vertical fixation disparity curves were made and a t-test for related measures was used to compare slopes. The x and y intercepts and slope data showed no significant differences between the groups. However, statistically larger measured associated phorias for the hypertensive group were found on all but one test. This suggests a relation between the magnitude of vertical associated phorias and the occurrence of essential hypertension, but the relation found was not of sufficient strength to warrant clinical application.