By guest blogger Michael Cohen:

In doctor's offices and hospitals, eye drop containers are sometimes shared between patients. Communal eye drops may be used in both outpatient and inpatient settings to prevent waste, control costs, and add convenience since it avoids constant inventory replacement. But some health professionals are concerned that communal containers might be contaminated, which could risk patient infection.

Existing medical literature does indicate that ocular cross contamination can occur. Preservatives ordinarily prevent bacterial growth in the solution but not all drops have them. Even so, bacteria may be present on bottle top inner surfaces or container grooves and tips due to touch contamination when the user does not wash their hands or because the tip of the container touched a patient's eyelid or eyelashes. Even tears should be considered a potentially infectious body fluid.

The labeling on some eye products suggests that medications should not be shared among patients. That goes for patients as well as health professionals. So after you finish treatment for your conjunctivitis, you'll want to discard remaining solution so you don't put others at risk.

I remember a study that was published years ago where someone examined 638 in-use containers and recovered bacteria from 82 (12.9%) of the bottles when dripped. Clinically and microbiologically significant growth was found in 12 cases (1.9%). Other studies confirm that in-use container contamination occurred, and that serious eye infections can be transmitted from such containers.

These studies also refute the belief that doctors, nurses and patients will always apply eye drops properly, without touch contamination. The likelihood of infection may increase for those with compromised immune systems or wounds such as penetrating eye injury or recent surgery. Yet it is doubtful that these patient conditions will always be screened effectively to prevent the use of communal drops.

Assurance of proper eye solution storage and disposal upon expiration is also difficult. Once, when I visited my ophthalmologist I noticed that the solution in a container holding epinephrine eye drops was black in color. That happens when the drug oxidizes after sitting around too long, reducing its strength and effectiveness. I don't use the same doctor anymore.

Medication errors, such as wrong drug and wrong concentration are also more likely with communal drops since patients' names are not on the container label. The American Academy of Ophthalmology long ago convinced leading ophthalmic manufacturers to color-code their ocular medications by therapeutic category and FDA agreed. Unfortunately though, this has led to mix-ups within each category because many distinctly different items now have identical color schemes, logos, fonts or other characteristics that make product differentiation difficult. A single dispensing error could affect multiple patients if someone keeps using the wrong container in error.

In human terms, the cost of an eye infection might be eye damage. Although that is unlikely it is certainly possible, especially if contamination occurs after eye surgery or injury. In financial terms the cost of treating even a single eye infection from cross contamination is high, which affects all of us in terms of health insurance premiums.

We've recommended that the smallest package size possible be used to assure containers won't remain in use on patient after patient but discarded after each use. Unit-of-use packaging is available for many commonly used eye medications. Still, manufacturers may not price these products attractively to promote their use. Alternatively, it may be possible for patients to fill prescriptions for eye medications prior to surgery, and bring them in for the procedure

For information on the Institute for Safe Medication Practices' consumer website go
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