Study	Reason for exclusion
Chen 2013	Intervention and comparator were not of interest. This study compared botulinum toxin with versus without sodium hyaluronate
Cooper 1991	The paper consisted of the preliminary findings for the paper by Lee 1994, which was excluded because the intervention and comparator were not of interest in this review update.
de Alba Campomanes 2010	Prospective, non‐randomized comparative study and not an RCT.
Doshi 2021	It was a comment and not an RCT.
Etezad Razavi 2014	Prospective, non‐randomised comparative study and not an RCT
Gursoy 2012	Retrospective review of botulinum toxin versus strabismus surgery outcomes for treatment of esotropia.
Jain 2015	Intervention and comparator were not of interest. This study compared botulinum toxin plus surgery with surgery alone.
Lee 1994	Intervention and comparator were not of interest. This study compared botulinum toxin with observation.
Li 2008	Prospective, non‐randomised clinical study and not an RCT
Mills 2004	Review article and not an RCT in itself
Minguini 2012	Intervention and comparator were not of interest. This study compared surgery plus injection of botulinum toxin (Prosign™) with surgery alone.
NCT03266549	Not intervention and comparator of interest. It compared augmented surgery by botulinum toxin with surgery alone.
Pandey 2021	It was a response to comments and not an RCT.
Sanjari 2008	Case series and not an RCT
Shallo‐Hoffman 2006	This was a case‐control study, not an RCT. Study of the influence of adaptation in people with chronic sixth nerve palsy having botulinum toxin.

Abbreviations: RCT: randomized controlled trial.