Glaucoma Filtration Surgery Related Endophthalmitis - Clinical Correlation and Visual Acuity Outcomes

Abstract

Abstract: : Purpose: To determine the clinical factors, causative micro-organisms, treatments, and visual outcomes of endophthalmitis associated with glaucoma filtration surgery. Methods: A retrospective, non-comparative case series of all patients treated for glaucoma filtration surgery related endophthalmitis at Casey Eye Institute, Oregon Health & Science University between July 1979 and May 2002. Only patients with blebs from glaucoma filtering procedures were considered. Patients with inadvertent blebs after cataract extraction were excluded. Results: Thirty-one (20%) of 155 eyes diagnosed with endophthalmitis had endophthalmitis related to glaucoma filtration surgery. Of these 31 eyes, 29 (94%) had prior trabeculectomy and 3 (10%) had valve implantation. Twenty-five (81%) had superiorly placed blebs. Fourteen (45%) of the eyes were phakic. Thirty (97%) of the eyes had vitreous samples cultured. Nineteen (63%) of the cultures were positive for bacterial growth. The most common causative organism was Streptococcus species in 9 (30%) eyes. The second most common causative organism was Staphylococcus in 6 (20 %) eyes. Twenty-four (77%) eyes underwent vitreous tap and injection of antibiotics while 7 (23%) underwent vitrectomy with antibiotic injection. Retinal detachment occurred in 8 (26%) of eyes. Four (13%) of the eyes were eventually enucleated due to a blind, painful eye. Pretreatment visual acuities were worse than 20/400 in 23 (77%) eyes. Final visual acuities were worse than 20/400 in 17 (61%) eyes. Final visual acuities in vitreous tap and injection group (n=23) versus the vitrectomy group (n=5) were as follows: worse than 20/400 (70% vs. 20%), 20/50-20/400 (9% vs. 80%), and better than 20/40 (22% vs. 0%). Mean duration of follow up was 441 days. Conclusions: Patients who develop endophthalmitis related to glaucoma filtration surgery generally have poor final visual acuity outcomes despite adequate medical and surgical treatment. In our study, Streptococcus and Staphylococcus species were the most common causative organisms cultured for endophthalmitis related to glaucoma filtration surgery. Additionally, the low rate of positive cultures found may impact how the microbiological specimens are processed in our institution.

Keywords: endophthalmitis • vitreoretinal surgery • clinical (human) or epidemiologic studies: out