Improvement in reading symptoms following botulinum toxin A injection for convergence insufficiency type intermittent exotropia

We evaluated injection of botulinum toxin A (BOTOX®, Allergan Inc., Irvine, CA) in patients with convergence insufficiency (CI) type intermittent exotropia (IXT) still symptomatic after convergence exercises. IXT can be divided into basic type, CI type and divergence excess type (Rosenbaum & Santiago 1999). CI type IXT is a common binocular vision disorder defined as an intermittent exodeviation at 10 PD or more at distance, and at least 10 PD...