Aqueous misdirection after glaucoma drainage device implantation

Objective: To describe the clinical presentation, outcome, and possible underlying mechanism of aqueous misdirection after glaucoma drainage device implantation. Design: Retrospective, noncomparative, interventional case series. Participants: Ten eyes (five primary open-angle glaucoma, four chronic angle-closure glaucoma, one nanophthalmos) of nine patients with a mean age of 68.5 ± 12.0 years (range, 43-83 years). Intervention: The authors reviewed the medical records of all patients with a clinical diagnosis of aqueous misdirection after Baerveldt glaucoma drainage device implantation at two tertiary care referral centers from October 1992 to October 1997. Surgery was performed in a standardized fashion; all drainage tubes were inserted in the anterior chamber and occluded with an external 7-0 polyglactin ligature. All eyes were treated with topical corticosteroids, cycloplegia, and aqueous suppressants. Eyes with persistent aqueous misdirection received neodymium:YAG (Nd:YAG) hyaloidotomy or pars plana vitrectomy. Main Outcome Measures: Visual acuity, intraocular pressure, biomicroscopic anterior chamber depth, and antiglaucomatous medication. Results: All eyes had axial shallowing of the anterior chamber, one or more patent iridotomies, and no ophthalmoscopic or B-scan ultrasonographic evidence of serous or hemorrhagic ciliochoroidal detachment. Median time to the development of angle-closure glaucoma was 33.5 days (range, 1-343 days) and mean intraocular pressure at diagnosis was 27.7 ± 18.7 mmHg (range, 10- 62 mmHg). Normalization of anterior segment anatomy was achieved with aqueous suppression and cycloplegia (one eye); Nd:YAG capsulotomy (four eyes); pars plana vitrectomy alone (two eyes) or with lensectomy (one eye), and pars plana vitrectomy with intraocular lens explanation (two eyes). Mean final intraocular pressure was 14.1 ± 6.0 mmHg at a mean follow-up of 9.1 ± 7.8 months after the development of aqueous misdirection (range, 1-23 months). Conclusions: Aqueous misdirection may develop days to months after glaucoma drainage device implantation. In this series, there was a poor response to medical therapy, and normalization in anterior chamber depth required aggressive laser and surgical therapy.