Associated Phorias With And Without Central Fusion Locks.

In this study, measurements of associated phorias taken-with two instruments possessing central fusion locks, the Barnell Box with fixation fisparity slide and the Borish Nearpoint
Card, are compared with measurements of associated phorias taken with an instrument having no central fusion lock, the Fixation Disparometer. Results of this study indicate that
measurements made with the two central fusion lack targets (the Borish Card and Barnell Box) are not signifiaantly different but measurements made with the Fixation Disparometer are significantly different from those found with the Borish Card. Measurements made with the Fixation Disparometer and Barnell Box did not correlate.