Orthoptic Treatment of Convergence Insufficiency: A Two Year Follow-up Report

Abstract

One theory of the etiology of convergence insufficiency is the presence of an underlying low AC/A ratio. In this study there were 207 patients with varying degrees of exophoria, but all with typical signs and symptoms of convergence insufficiency. It was clinically demonstrated that their asthenopia was caused by using excessive accommodative rather than fusional convergence. They were treated with home stereograms and followed for a two year period after treatment had been discontinued. Only those patients who progressed to the point of developing both fusional and voluntary convergence, indicated by their performance on the stereograms, maintained their increased convergence amplitude and remained asymptomatic for at least two years after treatment. These results indicate that a permanent alteration of the AC/A ratio had taken place.

• ocular convergence insufficiency
• relative NPC absolute NPC
• relative fusional convergence
• accommodative convergence
• asthenopia