Benefits from Vergence Rehabilitation: Evidence for Improvement of Reading Saccades and Fixations

Abstract

We hypothesize that binocular coordination of saccades is based on continuous neuroplasticity involving interactions of saccades and vergence. To test this hypothesis we study reading saccades in young students who were diagnosed for vergence disorders before and after vergence rehabilitation. Following orthoptic evaluation and symptomatology screening, 5 weekly sessions of vergence rehabilitation were applied with the REMOBI vergence double step protocole (see Kapoula et al., 2016). Using the Eyeseecam videoculography device we measured vergence as well as saccades and fixations during a reading test four times: at the beginning and at the end of the first and of the fifth vergence rehabilitation session. The results show elimination of symptoms, improvement of clinical orthoptic scores, and importantly increase of measured vergence gain and reduction of inter-trial variability. Improvement of the vergence was associated to a decrease of the disconjugacy of saccades during reading but also to shortening of fixation durations, to reduction of the number of regressive saccades and to a better correction of the intra-saccadic disconjugacy during the following fixation. The results corroborate the hypothesis of neuroplasticity based on saccade vergence interaction in young adults. It validates the clinical validity of the vergence double-step REMOBI method as a means to improve both, vergence and reading performances. It opens a new research approach on the link between fine binocular coordination of saccades, quality of the vergence response, attention, cognition and reading.

Induced vergence-accommodation conflict reduces cognitive performance in the Stroop test

“…Another important aspect is the weakening of the correlation between intra-saccadic disconjugacy and the disconjugacy during the following fixation. Previous studies showed significant correlation between these two parameters 38,61 ; such correlation was associated with a better capacity for reducing the disparity during fixation that results from the intra-saccadic disconjugacy. In the present study, the prisms altered this correlation that became weaker than in the lenses and in the control condition, and this for the interference Stroop task (see Fig.…”

Differential diagnosis of vergence and saccade disorders in dyslexia

“…This is an exciting area of research: though orthoptic training has been considered the standard of care rehabilitation for the dyslexic population, perhaps there are new avenues to design rehabilitation programs to train dyslexic adolescent eye movements to respond more quickly and accurately to these audiovisual stimuli. There have been some small preliminary studies that have already demonstrated improvement in reading (decreased regressive saccades, decreased fixation duration) in other populations 28 , 64 . In addition to the work that is currently being conducted, we would encourage more research in this exciting avenue specifically in the dyslexic population 65 .…”

“…On the other hand, perhaps these preliminary results related to eye movement deficits could be useful in planning retraining exercises. Previous studies using a double step vergence paradigm on the REMOBI machine have shown lasting improvements in reading saccades, fixations, and vergence measurements 19,28,[62][63][64] . Future research should repeat these experiments to verify audiovisual vergence retraining as a viable new rehabilitation technique.…”

“…A previous study showed that students who demonstrated vergence problems also demonstrated difficulty in binocular coordination of saccades and lower reading scores. After correcting these vergence abnormalities, the binocular coordination of saccades improved and reading improved (in terms of decreased fixation duration and a decrease in the number of regressive saccades) 28 .…”

Unstable Binocular Fixation Affects Reaction Times But Not Implicit Motor Learning in Dyslexia

“…Also, it seems worth researching whether monocular occlusion technique (as suggested by Stein and Fowler 67 ) or vergence training (orthoptic or optometric visual therapy), commonly used in case of heterophoria and/or other vergence anomalies, 68,69 may significantly improve fixation and motor control in dyslexia. The positive effect of vergence rehabilitation on saccades and fixation during reading was recently examined by Daniel et al, 70 but further studies in that area are necessary.…”