Characteristics and risk factors of infections after glaucoma filtering surgery

Purpose: To define characteristics and potential risk factors of endophthal mitis and blebitis after glaucoma filtering surgery in adults. Methods: A chart review of all cases of endophthalmitis or blebitis treated at the Duke University Eye Center for 6 years (January 1993 to December 19 98) was performed to identify patients with a history of incisional glaucom a surgery. Results: Twenty patients were identified. The filtering bleb was located su periorly in all patients. Blebitis but not endophthalmitis developed in 3 ( 15%) of 20 patients, and all had visual outcomes of at least 20/25. Endopht halmitis (blebitis and vitritis) occurred in 17 (85%) of 20 patients. Cases of blebitis were treated with topical antibiotics. All cases of endophthal mitis were treated with intravitreal antibiotics, and 3 (18%) of 17 patient s also underwent immediate vitrectomy. Initial visual acuity was less than hand motions in 5 (29%) of 17. Final visual acuity was less than 20/200 in only one case of endophthalmitis. In 15 (75%) of 20 patients, the bleb was noted to be thin, avascular, or both. On presentation, If (55%) of 20 blebs had Seidel-positive leaks with hypotony. A history of recurrent bleb leaks was documented in 7 (33%) of 20 patients. Pseudophakia was present in 13 ( 65%) of 20 eyes, and 7 (35%) of 20 had undergone combined cataract and filt ering surgery. A prodrome, such as a browache, headache, or external eye in flammation or infection, was documented in previous physician visits in 7 ( 35%) of 20 patients. No cases occurred in eyes with glaucoma implants. Conclusions: Patients in whom endophthalmitis develops after trabeculectomy do poorly, even with aggressive medical and surgical intervention. As expe cted, several patients had thin, avascular, leaking blebs. In addition, hyp otony, recurrent bleb leaks, pseudophakia, and more than one filtering surg ery may also be associated with blebitis or endophthalmitis after glaucoma filtering surgery. In a surprising number of patients, prodromal signs or s ymptoms were documented by ophthalmologists days or weeks before the diagno sis of blebitis or endophthalmitis was made.