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Multiple use of single use solutions: a dangerous practice
  1. D V Seal
  1. Correspondence to: D V Seal, MD, Applied Vision Research Centre, City University, Northampton Square, London EC1V 0HB, UK;

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I am writing to raise an issue for routine ophthalmic and optometry practice that contravenes the principles of clinical governance and generates an avoidable infection risk to patients.

My concern relates to single use preservative-free ophthalmic solutions, particularly those used for diagnostic purposes in hospital eye clinics and optometry practices. The regulatory guidelines1 and the updated guidance note from the Royal Pharmaceutical Society ( specify that products designed and licensed for single use must be discarded immediately after use.

In practice, however, a recent study2 has documented the routine misuse of single use solutions (Minims), generating an unnecessary risk of infection transferral between patients. Single use solutions used multiple times were shown to have a significantly higher rate of contamination than those that were used once then discarded (45% versus 4%). An associated audit (Qureshi MA, personal communication, 2004) of hospitals in the London region found that 86% of the ophthalmologists surveyed admitted to multiple uses of single use solutions between different patients.

The study demonstrated the principle that single use products could act as a vehicle for transmission of micro-organisms present on the practitioner’s hands or in the lid flora, if shared between patients. We know that gloves are typically not worn in outpatient ophthalmic practice, and that hands are not always washed between each and every patient. We note that even though the eye drop unit itself does not touch the patient’s eye or surrounding area, the practitioner often does touch the patient with his/her hands. Furthermore, the potential exists for infection transfer without physical contact. Aside from the risk of infecting the patient, the efficacy of the medication can be compromised in the event of contamination.

My own experience of ophthalmologists and hospital pharmacists indicates that in some cases the interpretation of the term “immediately” has been stretched beyond the simple instruction to “use once and discard.” For example, some published papers (Marchese et al3) refer to a, now outdated, EMEA instruction to use such products within three hours of opening. The EMEA has since replaced this with an updated guideline4 indicating that the usage time after opening is dependent on the nature of the product, yet this still encourages the user to retain the product for multiple use after first opening.

Clinical governance requires that risks and hazards to patients be reduced to as low a level as possible. Single use products are available for this purpose and should be used as intended and as licensed for one patient only. Repeated use in the same patient over a limited period up to 24 hours after first opening the product may be possible, depending on the product, and at the discretion of the clinician who must ensure that the product is not used on any other patient. I urge your readers to take action as necessary to ensure compliance.


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