Assessment of the effect of oral clarithromycin on visual outcome following presumed bacterial endophthalmitis

Purpose. The use of clarithromycin was assessed as a biofilm reducing agent in the management of bacterial endophthalmitis. Methods. 84 eyes of 83 patients presenting with clinical signs highly sugge stive of bacterial endophthalmitis were treated using a standard regimen of intraocular vancomycin, amikacin and systemic steroids, which in addition included oral clarithromycin. Ocular penetration of oral clarithromycin in healthy and inflamed eyes was also assessed. Results. Comparing visual acuities at presentation and 6 months, 66% of pat ients demonstrated an improvement. Intraocular samples were culture positiv e in 58% of eyes. As compared to culture positive cases, more culture negat ive cases achieved a visual acuity of 6/12 or better (p = 0.0047). As compa red to patients receiving the standard protocol but without clarithromycin, a greater number of culture negative cases demonstrated an improvement in vision of greater than or equal to + 6 Snellen lines (p = 0.023). The ocula r penetration of clarithromycin into the anterior chamber of inflamed eyes appears sufficient to allow anti-biofilm activity against bacteria at the b asic pH encountered in eyes with endophthalmitis. Conclusions. The ocular penetration of clarithromycin appears adequate for anti-biofilm activity in inflamed eyes. The beneficial effects of oral clar ithromycin on visual outcome has been demonstrated in culture negative eyes with clinical signs highly suggestive of bacterial endophthalmitis. The fi nal visual outcome for culture positive cases remains poor.