Skip to main content

Validation of the Butler test for detection of vertical fixation disparity

6 February 1981


A general review of fixation disparity and Panum's fusional areas preceeded a more specific discussion of vertical fixation disparity. Included were a summary of factors affecting fixation disparity, symptomatology and methods of prescribing for vertical imbalance. The Butler test was compared with the AO Nearpoint Vectographic Card #1 regarding their ability to detect induced vertical misalignment. Results of the parametric statistics, using a t-test, indicated that there was no significant difference between the two methods in detecting vertical misalignment.


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