Strabismus following implantation of Baerveldt drainage devices

Objective: To describe the clinical features of strabismus following implantation of a Baerveldt glaucoma seton. Design: Case series of four patients with a minimum follow-up of 6 months. Setting: Specialized glaucoma referral center at Bascom Palmer Eye Institute/Ann Bates Leach Eye Hospital, Miami, Fla. Patients: Consecutive sample of four patients with persistent binocular diplopia following implantation of a 350-mm 2 Baerveldt glaucoma seton in the superotemporal quadrant. Results: Each patient presented with a characteristic pattern of either exotropia or hypertropia, or both. The deviation increased with gaze opposite the ipsilateral superior and lateral muscles and decreased in the field of action of the involved muscles. All patients demonstrated a convergence insufficiency type of exotropia. Conclusion: These patients presented with a similar type of restrictive strabismus. Proposed mechanisms include an increase in the length-tension curve of the muscle induced by the underlying bleb and a posterior fixation effect as a result of scarring behind the implant.