There's a large double blind treatment trial that was administered by the National Eye Institute. It's called the convergence insufficiency treatment trial. And in that study they looked at what was the most effective treatment for an eye teaming condition called convergence insufficiency. And the results of the study clearly showed that the most effective treatment was in office vision therapy performed by a skilled and trained therapist combined with home based activities. The other two treatment options that were compared to were computer based therapy and home based exercises alone. And definitively it showed that it was most effective when it was done in office and supplemented with home based activities.
Conservative estimates suggest that at least 5% of children have convergence insufficiency, however there are many other clinical studies from around the world that show a much higher prevalence. It is estimated that by the age of 90, 70% of people will have been diagnosed with convergence insufficiency at some point in their life.
There was a second portion to that study that was done a few years later, and that one looked at the benefit of vision therapy to treat convergence insufficiency and the effect that that has on reading. The conclusion was ultimately that treating convergence insufficiency alone is not significant enough to improve reading just by itself. I think that in a case like that with one of those studies, we also have to question is, are there also other types of disorders, auditory processing, visual processing, other things besides just it being that may factor into the effectiveness of that.