Infectious endophthalmitis after glaucoma drainage implant surgery

Purpose: To report the clinical features, microbial spectrum, and treatment outcomes of endophthalmitis after glaucoma drainage implant (GDI) surgery. Methods: Records of patients diagnosed with endophthalmitis after GDI surgery were reviewed. Data on clinical course, microbiological laboratory results, and treatment were analyzed. Results: Of 1,891 eyes that underwent GDI surgery, 14 eyes (0.7%) developed endophthalmitis. The mean time interval between GDI surgery and diagnosis of endophthalmitis was 2.6 ± 3.2 years (median, 1.3 years; range, 11 days-11.4 years). For initial treatment, 13/14 eyes underwent vitreous tap and injection of intravitreal antibiotics and 1/14 eyes underwent primary pars plana vitrectomy. Three additional eyes underwent pars plana vitrectomy because of deteriorating clinical course. Glaucoma drainage implant erosion was present in 9/14 eyes. All 9 eroded GDIs were surgically removed within a mean of 9 ± 5 days (range 2-29 days) after diagnosis of endophthalmitis. Overall, mean logarithm of the minimum angle of resolution best-corrected visual acuity worsened from 0.7 ± 0.7 (Snellen equivalent 20/100) at baseline to 1.6 ± 1.1 (Snellen equivalent 20/800) at final follow-up (P = 0.005). Mean duration between the onset of symptoms and presentation was significantly longer in patients with decreased final best-corrected visual acuity (>2 Snellen lines) compared to patients with stable final best-corrected visual acuity (6.8 vs. 1.0 days; P = 0.005). Conclusion: Glaucoma drainage implant-related endophthalmitis is rare and often associated with GDI erosion. Patients who presented earlier after the onset of symptoms had better final visual outcomes. Prompt evaluation and treatment is required, often with removal of the eroded GDI.