Botulinum Toxin for Strabismus following Retinal Surgery
Sonia S. Moorthy; Maria Theodorou; Joanne Hancox; Gill Adams
Moorfields Eye Hospital
Introduction: Botulinum toxin treatment is acknowledged as an acceptable alternative in the management of complicated strabismus.1 We provide an updated review of our experience with botulinum toxin for strabismus following retinal surgery.
Methods: A retrospective case file review of all patients who received botulinum toxin treatment for strabismus following retinal detachment surgery at Moorfields Eye Hospital, London between January 2006 till August 2017.
Results: 20 patients fulfilled our criteria. Mean length of follow-up was 20 months.
Main presenting symptoms were diplopia (65%) and poor cosmesis (35%). 12/20(60%) had detached macula pre-operatively. Cryobuckle (20%) and vitrectomy (80%) accounted for the retinal surgeries performed.
9/20(45%) had vision of 6/60 or worse in the affected eye. Exotropia (75%), esotropia (15%) and hypertropia (10%) accounted for the manifest deviations. Mean angle (near and distance) was 40PD. Patients received a mean of 2.5 toxin injections, with a reduction in the angle of deviation by half or more in 9/20(45%). Of the decompensated phorias (5/20), 80% regained single vision. 10/20(50%) demonstrated poor response to toxin. 1/20(5%) subsequently underwent strabismus surgery.
3/20(15%) developed a transient consecutive esotropia and 1/20(5%) developed a persistent secondary vertical deviation. Intractable diplopia was noted in 1/20(5%).
Discussion: Botulinum toxin often restores binocularity in patients with pre-existing fusion potential. Ocular cosmesis can be achieved but requires ongoing injections. Factors related to poor response to toxin treatment include: multiple retinal surgeries, concurrent macular pathology and pre-existing sensory strabismus.
Conclusion: Botulinum toxin represents a safe alternative to strabismus surgery in a selected group of patients.
References: 1. Gardner R, Dawson EL, Adams GG, Lee JP. The use of botulinum toxin to treat strabismus following retinal detachment surgery. Strabismus 2013;21(1):8-12.