Vergence Eye Movements Flashcards
What are the 4 Maddox classifications of vergence?
Tonic
Proximal
Accommodative
Fusion (Disparity)
When can disparity vergence only be sustained?
when the two eyes have quite similar, or “correlated” images. (“Slow” component)
What component takes over the maintenance of static eye position alignment?
Slow component
When can disparity vergence be initiated?
when the two eyes have dissimilar, or “uncorrelated” images with a retinal disparity between the two. (fast component)
What component responds rapidly to changes in retinal disparity?
fast component
3 characteristics of vergence disparity
1) Disparity vergence will fuse two blurry lines about as well as two sharply-focused lines.
2) Changes in contrast and luminance of the stimulus don’t have much effect on disparity vergence.
3) Disparity vergence velocity increases as the correlation between the left and right eye images increases.
Relationship between amplitude and peak velocity
Peak velocity increases as amplitude increases with a ration of 4:1
2 types of vergence adaption
Prism adaption
Asymmetric vergence adaptation in spectacle-based anisometropia.
The asymmetric disparity changes (with/without) direction of gaze.
With direction of gaze
What is vision therapy?
visual-feedback based neuro-motor conditioning or enhancement
What happened to the group of subjects who trained their vergence system?
Improved blur/break/recover values at distance and near and also negative fusional vergence values.
What does vision therapy change?
more rapid onset of vergence adaptation, reducing phoria
Adaptation of accommodation has greater efficiency to ___________________________________.
Slow gradual changes in accommodation.
The phasic controller represents what?
fast component, responds to perceived blue.
The tonic controller limiter represents what?
slow, adapting component, responds to (and builds up) input of phasic controller.
