Evaluation of an extended period of use for preserved eye drops in hospital practice.

AIM To evaluate and compare the microbial contamination arising from 1 and 2 weeks' use of eye drops by hospital inpatients and hence determine the validity of apportioning a 2 week in use expiry date for these preparations. METHODS Eye drop residues were collected from inpatients of Worthing, Southlands, and Brighton General hospitals after 7 days' use (341 samples) and also after 14 days' use (295 samples). The contents of the containers were examined for the presence of contaminating bacteria and fungi. RESULTS The incidence of microbial contamination was shown to be not significantly different (p > 0.1 chi 2 test) between the 7 and 14 day samples. In addition, the contaminating micro-organisms were of a broadly similar pattern between the two sample groups and were mostly those normally associated with the skin. Less frequent contaminants were organisms of environmental origin. None of the micro-organisms isolated were considered to be of clinical significance and the mean number of cells found per sample was very low. CONCLUSIONS The evidence therefore suggests that increasing the period of use for eye drops in hospitals from 7 to 14 days would not present a clinically significant threat to patients' health and yet may lead to annual savings to the NHS of Pounds 0.5 million.