Binocular Vision and Accommodative Anomalies

The main binocular vision and accommodative anomalies are considered in turn: strabismus, heterophoria, convergence insufficiency, binocular instability, accommodative insufficiency, and accommodative infacility. For each of these conditions, any associations with reading difficulties are reviewed. Each review includes an assessment as to whether the anomaly may contribute causally to reading difficulties. The treatment of these conditions is discussed, also addressing the general question of when optometric factors need to be treated. The chapter closes with a table summarising the above conditions. It is concluded that binocular instability (fusional vergence dysfunction) is correlated with dyslexia, but is unlikely to be a major cause of the condition.