The influence of vergence adaptation on open-loop vergence dynamics

Vision Res. 2009 Jul;49(14):1795-804. doi: 10.1016/j.visres.2009.04.015. Epub 2009 Apr 21.

Abstract

The objectives of this experiment were to measure the effect of sustained convergence on the open-loop vergence peak velocity and open-loop vergence amplitude, and to assess the correlation between changes in the phoria and changes in open-loop vergence peak velocity induced by sustained convergence. Subjects sustained convergence on a target that required 12 degrees of convergence for 5 minutes. Convergence and divergence movements of 4 degrees from the 12 degrees convergent position were measured before and after sustained convergence. Following sustained convergence, the open-loop vergence peak velocity and vergence amplitude both increased for convergence (regression slope=3.68, r=0.47). Vergence velocity and vergence amplitude both decreased for divergence (regression slope=1.76, r=0.36). After sustained convergence, a convergent shift in the phoria was noted in most cases. This shift correlated with changes in open-loop peak vergence velocity more for convergence (regression slope=1.1, r=0.33) than for divergence (regression slope=0.71, r=0.22). The results might be due to shifts in disparity detection brought about by the period of sustained convergence.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Accommodation, Ocular / physiology
  • Adaptation, Ocular / physiology*
  • Adult
  • Convergence, Ocular / physiology*
  • Eye Movements
  • Female
  • Fixation, Ocular
  • Fourier Analysis
  • Humans
  • Male
  • Photic Stimulation
  • Reaction Time
  • Refractive Errors
  • Young Adult