Antimicrobial prophylaxis can decrease the incidence of infection, particularly surgical site infection, after certain procedures. Recommendations for prevention of surgical site infection are listed in this article.

Many prescriptions for eye drops call for instillation of 1-2 drops. But Medical Letter consultants in ophthalmology seem to agree that all eye drops should generally be given in doses of only one drop.

The volume of a single drop can vary with the viscosity of the solution, the design of the dropper, and patient technique. The average volume of a drop is 35-50 microliters, but can be as high as 75 microliters. An eye brimming with fluid holds 30 microliters at best, so even one drop is often an overdose. A second either washes out the first or increases the possibility of systemic toxicity, and doubles the cost.

When two different drops are being used, they should be instilled at least 5 minutes apart.