Abstract
Strabismus in the presence of a glaucoma drainage device (GDD) can be sensory in cases of advanced glaucoma or caused by the implant itself. Either way, surgical management of such patients’ strabismus is technically challenging and associated with increased risk. Botulinum toxin injections to the extraocular muscle overlying the GDD may provide an effective and lower risk alternative. We present a series of patients with strabismus and GDDs who underwent toxin injections.
The medical records of all patients in a local hospital with GDDs who had botulinum toxin injections to the overlying muscle for strabismus over a 5-year period were retrospectively examined. Patients could have any GDD type and were assessed 2-4 weeks after their injection.
29 patients met the inclusion criteria. 25 patients had Baerveldt, 3 had Paul and 1 had a combination of Molteno and Baerveldt tubes. 15 had sensory exotropia, 9 restrictive or mass effect exotropia and 5 had other causes of exotropia. There was an average improvement in deviation after 1 injection from 43PD to 17PD for near and 39PD to 13PD for distance. Of these, 14 patients received a top-up injection and 4 had a further improvement in deviation of over 10PD. 2 patients had a temporary induced vertical strabismus. No other complications were reported. Overall, 72% of patients were satisfied with the effect of their injection.
Toxin injections in patients with GDDs represent a safe and effective treatment. It may be a valid alternative to surgery, which is often contraindicated and technically challenging.