Delayed-Onset Endophthalmitis Associated With Glaucoma Drainage Implant

Summary

Glaucoma drainage implant (GDI) delayed-onset endophthalmitis – Most cases from tube or plate exposure. VA outcomes generally poor. Retrospective, 45 eyes.

Abstract

Purpose: To report the clinical presentations, microbial spectrum, management approaches and outcomes of endophthalmitis associated with glaucoma drainage implants (GDIs).

Design: Retrospective, non-comparative, consecutive case series at a single tertiary referral center.

Subjects: Medical records of all patients treated for GDI-associated endophthalmitis from 2013 to 2024 were reviewed.

Methods: Cases were identified by querying institutional databases using the CPT codes 66180/66179/66185 (aqueous shunt procedure) or 65920 (removal of implanted material, anterior segment) or 67120 (removal of implanted material, posterior segment; extraocular) with the ICD-10 code of H44.0X for purulent endophthalmitis. Only patients with documented vitritis, endophthalmitis or culture positive vitreous aspirations were included.

Main outcome measures: Outcome measures included the following: duration of follow-up, performing enucleation, need for additional surgery for glaucoma control, BCVA and IOP at the last follow-up examination.

Results: The current study included 45 eyes of 45 patients were identified. The onset of endophthalmitis ranged from 6 weeks to 11 years after GDI placement, with a median interval of 4 years. Tube or plate exposure was present in 73% of cases at the time of diagnosis, with an additional 18% having recent conjunctival revision for prior exposure. Cultures were positive in 51% of cases; S. epidermidis in 4, S. aureus in 3, Streptococcus in 2, mycobacterial in 4, gram negative in 8 and fungi in 2. Initial management included intravitreal antibiotics for all eyes, with adjunctive pars plana vitrectomy in 40%. Initial treatment with conjunctival revision of tube exposure was performed in 2 eyes, but ultimately all eyes had explantation of the tube. Despite prompt treatment, visual outcomes were poor with only 22% of eyes achieving 20/200 or better visual acuity and 7 eyes with no light perception. Additional glaucoma surgery was performed for IOP control in 12 eyes and 4 had retinal detachment surgery. Enucleation was performed in 1 eye.

Conclusion: Delayed-onset endophthalmitis is a devastating complication after GDI surgery, and most cases are associated with tube or plate exposure. Visual acuity outcomes are generally poor.