Occurrence of motility disorders in patients undergoing tube surgery-consecutive, retrospective follow-up case series analysis.

BACKGROUND: The two glaucoma drainage devices (GDD) Ahmed and Baerveldt tubes are most commonly used for the treatment of refractory glaucoma. We noticed a significant number of patients with postoperative motility disorders resulting in diplopia. We investigated the occurrence and patterns of postoperative motility disorders overall and between the two GDD tubes using the Hess Screen Test. METHODS: Retrospective single-center matched case series of 20 patients undergoing Ahmed and 20 patients undergoing Baerveldt tube implantation with a follow-up of at least 1 year. In order to investigate the dynamic of GDD-induced motility disorder over time, from 25 patients, a follow-up examination from two different time periods (3 to 6 months and 12 to 24 months postoperatively) was available. From these 25 patients, 12 had received an Ahmed and 13 a Baerveldt GDD. To compare the different Hess Screen Tests, we developed nine categories of possible emerging motility disorder in the operated eye as a primary endpoint: Motility restriction in up-gaze, in down-gaze, in abduction, in adduction; combined motility disorders in up-gaze and adduction, up-gaze and abduction, down-gaze and adduction, down-gaze and abduction. If there was no motility disorder, this was also separately classified. RESULTS: Regardless of the used device, Ahmed or Baerveldt, most patients experienced motility disorders to some extent; mainly down-gaze and adduction were affected. However not every motility disorder resulted in diplopia. Although over time a decrease in ocular misalignment was seen, the incidence of diplopia was stable. Nevertheless, only few required therapy. We noted no difference between Ahmed and Baerveldt tube implant devices. CONCLUSION: Ocular misalignment and restriction of motility is a common finding after GDD. Although not every motility disorder results in diplopia, it is frequent. Therefore, it needs to be taken into consideration in informed consent.