A Study Of Slow Vergence Adaptation Using Forced Vergence Fixation Disparity Curves.

There i s a general belief tha t the slope of thestandard
forced-vergence fixation disparity curve is an indication of
patient comfort, with the steeper curves more often associated
with a asthenopia: When fixation disparity measurements are taken,
it usually takes at least 15 seconds to generate each point on the
curve. The works of Carter and Schor have suggested that this is enough time for a slow prism adapt ion cycle to be set in motion. . It
therefore seems likely that per0on s with e~f icient prism adap t a tion
mechanisms will produce flatter fixation disparity curves . Indeed,
Schor) did find a high correlation between efficient slow
vergence adaptation to small amounts of fixation disparity .
A difference between the slopes of the prism induced fixation
disparity curves before and after slow prism adaptation has been
initiated should be easy to demonstrate . The amount of the difference
between the two curves should be related to the efficiency
of the patient 's slow vergence adaptation mechanism.