Skip to main content

The effect of vertical prism induced stress on the accommodation and vergence ranges

1 May 1993


This paper presents a study of the effect a vertical imbalance has on the lateral vergence and accommodation ranges as measured in standard clinical testing. The clinical tests included lateral duction ranges at 6 meters and 40 centimeters, the positive relative accommodation (PRA), and the negative relative accommodation (NRA). Nineteen subjects considered visually normal were tested once with two prism diopters of induced vertical imbalance, and once under normal conditions. An ANOV A was performed on the means of thirteen clinical tests . The F-test and probability values are also presented . Results indicate that the findings of the tests with the vertical prism in place were not different from the findings with no pr ism in place.


Files are restricted to Pacific University. Sign in to view.