We report three cases of esotropia after botulinum toxin A injection in the eyelid for esthetic purposes.

Esotropia was observed in three patients presented with diplopia after botulinum toxin A application in the eyelid for esthetic purposes. (Case 1) A 51-year-old woman developed diplopia, mild ptosis and hyperemia in both eyes after periocular cosmetic use of botulinum toxin A 6 weeks before. In the primary position, the angle of esotropia was 10 prism diopters (PD) at distance and 6 PD at near. She had slightly limited abduction and mild ptosis on both eyes. (Case 2) A 50-year-old woman developed diplopia after botulinum toxin A injection in the upper eyelid 15 days prior. In primary position, the angle of esotropia was 18 PD at distance and 12 PD at near. She had slightly limited abduction and mild ptosis in both eyes. (Case 3) A 40-year-old woman was examined with diplopia after botulinum toxin A injection in the crow's feet and lower lid 6 days earlier. In primary position, the angle of esotropia was 30-35 PD at distance and 18 PD at near. She had slightly limited abduction. Prism glasses were prescribed for patients in case 1 and case 3. All three patients were resolved in symptoms of diplopia, gaze limitation and ptosis after 1 or 2 months.

Botulinum toxin A could spread out from the lateral canthus to both lateral rectus muscles and cause a transient paresis of the muscles. This was presented as esotropia and the mild abduction deficits on both eyes. We suggest that patients presenting with diplopia should be asked if they have a history of injection of botulinum toxin A and patients should be fully informed about the complications of botulinum toxin A before injection.