Tuesday, July 22, 2014

Eye movement (oculomotor) rehabilitation


A recent study noted that people with traumatic brain injury often have a constellation of eye movement (sometimes called oculomotor) deficits. The study noted that over 90% of patients with mild traumatic brain injury (sometimes abbreviated TBI and sometimes called acquired brain injury) were found to have one or more oculomotor dysfunctions.

The vision rehabilitation therapy that we provide in our vision therapy clinic, sometimes called oculomotor rehabilitation or oculomotor training, is effective in providing significant improvement in eye motor disorders that result from traumatic brain injuries ranging from concussions, severe head injuries and strokes.

Disorders of convergence and divergence

A study entitled "Effect of oculomotor rehabilitation on vergence responsivity in mild 
traumatic brain injury", published in 2013 in the Journal of Rehabilitation Research & Development examined a group of patients before and after they received oculomotor training and placebo therapy to determine whether there was improvement in their convergence and divergence ability. Convergence refers to the way the eyes move inward or converge when doing near work. Divergence refers to the ability of the eyes to move outward or diverge when focusing on objects that are moving away from the body.

The researchers found that convergence and divergence abilities improved significantly following oculomotor training, as did depth perception and visual attention. No improvement resulted from placebo therapy, suggesting that the the rehabilitation therapy was effective and that no improvement is expected in the absence of therapy.

The authors concluded that there was "overall improvement in nearly all of the critical, abnormal measures of vergence was observed both objectively and clinically. Improved vergence motor control was attributed to residual neural visual system plasticity and oculomotor learning effects in these individuals."

Disorders of accommodation


A 2014 study entitled "Effect of oculomotor rehabilitation on accommodative responsivity in mild traumatic brain injury" and also published in the Journal of Rehabilitation Research & Development looked at the effect of vision therapy rehabilitation for a group of oculomotor dysfunctions known as "accommodation". Accommodation refers to the ability of the eyes, through a complex neurological process, to change optical power to maintain a clear image or focus on an object as its distance from the eyes varies.

The researchers looked at 12 patients with mild traumatic brain injury who had vision related symptoms and gave them a program of rehabilitative oculomotor training (lasting six weeks with two three hour sessions per week) as well as placebo therapy. The researchers found that the rehabilitation program produced significant improvement in the patients' accommodation abilities. No improvement was found following placebo therapy. The authors conclude that "[t]hese results provide evidence for a significant positive effect of the accommodatively based OMT on accommodative responsivity. Such improvement is suggestive of oculomotor learning, demonstrating considerable residual brain-visual system plasticity in the adult compromised brain."

The statistic in the graphic that accompanies this post comes from a 2008 study by Ciuffreda et al. published in the journal Optometry which found that  90% of patients with traumatic brain injury who were treated with vision therapy had significant improvement in their eye movement disorders.