A Cochrane review on antibiotic therapy in the management of acute bacterial conjunctivitis included 11 trials with a total of 3 673 subjects. One further trial is awaiting assessment. The studies examined 0.6% besifloxacin ophthalmic suspension (3 studies), 1% fusidic acid gel, 1% azithromycin in DuraSite, 0.5% moxifloxacin, a new formulation of moxifloxacin containing xanthum gum so as to be retained in the eye, polymyxin+bacitracin ophthalmic ointment, and 0.3% ciprofloxacin, 0.3% norfloxacin, and 0.5% chloramphenicol eye drops (1 study each). Nine trials were conducted on a selected specialist care patient population and two in a community care setting. Topical antibiotics improved early (days 2 to 5) clinical (RR 1.36, 95% CI 1.15 to 1.61) and microbiological (RR 1.55, 95% CI 1.37 to 1.76) remission rates. At the 'late' time point (days 6 to 10), antibiotics were found to still confer modest benefits in clinical remission (RR 1.21, 95% CI 1.10 to 1.33) and microbiological cure rates (RR 1.37, 95% CI 1.24 to 1.52). By days 6 to 10, 41% (95% CI 38 to 43) of cases had resolved in those receiving placebo. No data on the cost-effectiveness of antibiotics were found. No serious outcomes were reported in either the active or placebo arms of these trials.
Another systematic review analyzing individual patient data included 3 primary care trials including a total of 622 subjects. Eighty per cent (246/308) of patients who received topical antibiotics and 74% (233/314) of controls were cured at day 7. There was a significant benefit of antibiotics versus control for cure at seven days in all cases combined (risk difference 0.08, 95% CI 0.01 to 0.14). Subgroups that showed a significant benefit from antibiotics were patients with purulent discharge (risk difference 0.09, 95% CI 0.01 to 0.17) and patients with mild severity of red eye (risk difference 0.10, 95% CI = 0.02 to 0.18), while the type of control used (placebo drops versus nothing) showed a statistically significant interaction.
Comment: The quality of evidence is downgraded by study limitations (lack of/unclear allocation concealment, possibly selective recruitment).