1. Botulinum toxin versus observation.

Study ID	Total participants	Primary: improved ocular motility	Secondary: improved binocular single vision	Secondary: improved symptoms	Secondary: adverse events
Lee 1994	47, parallel arm RCT 22 ‐ botulinum toxin 25 ‐ observation 6 month follow‐up	21 (95.5%) ‐ botulinum toxin 20 (80%) ‐ observation	Success: 21 (95.5%) ‐ botulinum toxin 20 (80%) ‐ observation Partial: 3 (12%) ‐ observation Fail: 1 (4.5%) ‐ botulinum toxin 2 (8%) ‐ observation	21 (95.5%) ‐ botulinum toxin 20 (80%) ‐ observation	9% ptosis 18% vertical deviation

RCT: randomised controlled trial