Nonstrabismic binocular dysfunction is one of the most commonly reported conditions in nonpresbyopic subjects with asthenopic symptoms worldwide. These are vision disorders which mostly affect the binocularity and visual performance of subjects particularly with difficulty in near vision. They are mainly categorized into vergence anomalies and accommodative anomalies. There is a wide variations in the prevalence of these vision disorders. The differences exist because of different diagnostic criteria used in the earlier studies. However there is a lack of consensus in the scientific...