Characteristics and risk factors of infections after glaucoma filtering surgery

To define characteristics and potential risk factors of endophthalmitis and blebitis after glaucoma filtering surgery in adults.

A chart review of all cases of endophthalmitis or blebitis treated at the Duke University Eye Center for 6 years (January 1993 to December 1998) was performed to identify patients with a history of incisional glaucoma surgery.

Twenty patients were identified. The filtering bleb was located superiorly in all patients. Blebitis but not endophthalmitis developed in 3 (15%) of 20 patients, and all had visual outcomes of at least 20/25. Endophthalmitis (blebitis and vitritis) occurred in 17 (85%) of 20 patients. Cases of blebitis were treated with topical antibiotics. All cases of endophthalmitis were treated with intravitreal antibiotics, and 3 (18%) of 17 patients 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, 11 (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 filtering surgery. A prodrome, such as a browache, headache, or external eye inflammation or infection, was documented in previous physician visits in 7 (35%) of 20 patients. No cases occurred in eyes with glaucoma implants.

Patients in whom endophthalmitis develops after trabeculectomy do poorly, even with aggressive medical and surgical intervention. As expected, several patients had thin, avascular, leaking blebs. In addition, hypotony, recurrent bleb leaks, pseudophakia, and more than one filtering surgery may also be associated with blebitis or endophthalmitis after glaucoma filtering surgery. In a surprising number of patients, prodromal signs or symptoms were documented by ophthalmologists days or weeks before the diagnosis of blebitis or endophthalmitis was made.