Botulinum toxin in childhood strabismus

Abstract

The use of botulinum toxin A (BTXA) in childhood strabismus is still a matter of debate. This study investigates the indications for and outcome of BTXA therapy in children at our institution. From 1985 to 1995, 237 children up to and including 16 years of age were treated with BTXA for strabismus. We undertook a retrospective study of 163 (69%) children from this group. Factors considered were age; anaesthesia; number of, indication for and outcome of injections; complications and follow-up. There were three major indications for the use of BTXA in children: firstly to improve binocular function, secondly as a post-operative diplopia test or for cosmetic reasons, and thirdly in the investigation or treatment of paralytic and restrictive strabismus. In the first group (54 children), BTXA produced improved binocular function in 54% of all patients treated and in 49% of those with a minimum follow-up of 12 months. In the second group (82 children), 88% showed informative post-operative diplopia tests and 44% had more than one injection to maintain improved cosmetic alignment. The third group comprised 27 children with a range of diagnoses, including 1 third nerve paresis, 12 unilateral or bilateral sixth nerve pareses, 7 unilateral or bilateral Duane's syndromes, 5 lost or fibrosed muscles and 2 others. This group had a range of outcomes which are discussed in the text. BTXA is useful in the treatment of a select group of children with strabismus. If there is evidence of threatened or recently lost binocularity, or risk of creating or worsening diplopia after surgery, it is a useful therapeutic tool. In children with strabismus of unusual cause it has diagnostic value.

The Role of Botulinum Toxin in Decompensated Strabismus

“…There have been several reports in children (Ing, 1993;McNeer et al, 1998;Scott et al, 1989;Spencer et al, 1997). Rayner et al (1999) suggested that, in particular, children with decompensating intermittent exotropias and postoperative consecutive esotropias with a potential for binocularity were most likely to benefit. There are but a few studies that discuss the utility of botulinum toxin to cure adult decompensated squint (Rowe & Noonan, 2007;Rowe et al, 2005).…”

Double vision

“…This also serves to prevent medial rectus contracture [5•, Class I]. Another indication for chronic botulinum use is in patients considered poor surgical candidates and surgically overcorrected patients [6,7,Class III].…”

Advanced Functional Oculofacial Indications of Botulinum Toxin

“…76 Side effects include transient ptosis, subconjunctival hemorrhage, and hypotropia. 74 Bilateral lateral rectus injections have been used for the treatment of childhood intermittent exotropia. 80 Although orthophoria was obtained in 69% of patients, these results are not as successful as those obtained with treatment of infantile esotropia.…”

“…68,69 Successful results have been obtained after botulinum toxin A injections for infantile esotropia. [70][71][72][73][74][75][76][77][78][79] Intervention before 7 months of age in congenital esotropia provides better results of long-term alignment 71 and as many as 66% of patients can develop stereopsis, with early treatment. 76 Side effects include transient ptosis, subconjunctival hemorrhage, and hypotropia.…”