Open drops in ophthalmology offices: expiration and contamination

To determine the relationship between eye drop use and contamination rate in ophthalmology offices.

Following permission request, open bottles were examined and the nozzle tip and one drop of content was cultured on solid media.

Drug category, volume, weight compared to full, clean legible label, expiration date; 2 or more bacterial colonies along the inoculation site.

In 18 offices, of 1,485 open bottles (mean 12.2, range 4 to 23 per lane) on average 19.8% (range 0% to 88%) were expired (16.2 of 82.5 bottles per office). The frequency of occurrence (%) and expiration (%E) were 40.3% cycloplegics (19.4%E); 16.4% glaucoma (33.7%E); 10.8% anesthetics (8.8%E); and 4% steroids (8.8%E; or 42.2%E including one outlier). Most likely expired were glaucoma (P < 0.001); small 2-3 ml (P < 0.02), nearly empty (P < 0.05), or dirty (P < 0.001) bottles. Only one (5 ml cyclopentolate, not expired) grew a Micrococcus (0.07%).

Drops in ophthalmology offices may be expired but are not contaminated.