Antibiotic prophylaxis in eyes with filtration blebs: survey of glaucoma specialists, microbiological study, and recommendations.

PURPOSE: Bleb-related endophthalmitis is a major late complication of filtration surgery. The purpose of this study was to determine the ophthalmic practic patterns regarding long-term antibiotic prophlaxis in eyes with filtration blebs, and the effect of long-term antibiotic usage on conjunctival bacterial flora.
METHODS: A mail survey of members of the American Glaucoma Society (AGS) was undertaken. In addition. 41 patients who had filtation surgery and received long-term topical antibiotic therapy in one eye only had conjunctival cultures performed in both eyes.
RESULTS: Of the responding members of the AGS, only 6% routinely prescribed long-term antibiotic prophylaxis, 28% prescribed therapy in selected cases only, and 66% did not employ antibiotic prophylaxis. Although more physicians than not had observed endophthalmitis in patients not receiving antibiotic therapy, it was evident that antibiotic prophylaxis did not guarantee that endophthalmitis would not develop in a filtered eye. A total of 49 organisms were isolated from the conjunctiva of eyes receiving antibiotic prophylaxis and 52 organisms were isolated from eyes not receiving antibiotic prophylaxis. There was no statistically significant difference in the types of organisms isolated.
CONCLUSION: Long-term antibiotic prophylaxis does not appear to be a common practice among glaucoma specialists in this country, and it cannot be depended upon as a fail-safe method to prevent bleb-related endophthalmitis. Furthermore, long-term antibiotic usage does not appear to alter the conjunctival flora. Of paramount importance are early detection and treatment of bleb-related infections. Critical in this regard is patient education. Recommendations to minimize the development of endophthalmitis in filtered eyes are reviewed.