Repeated use of preservative-free dexamethasone 0.1% eye drops within 24 hours does not increase bacterial contamination
A study determined that repeated use of preservative-free single-dose unit (SDU) dexamethasone 0.1% eye drops within a 24-hour period does not increase bacterial contamination. This investigation addresses concerns regarding off-label repeated use of SDUs, which are designed for single use but are often reused by patients.
In this prospective study, published in BMJ Open Ophthalmology, 109 patients scheduled for corneal and glaucoma surgery were enrolled. Each patient received dexamethasone 0.1% eye drops four times daily from the same vial. Bacterial contamination was assessed by culturing drops immediately after opening the SDU (t0), 10 hours later after four applications (t10), and 24 hours after opening without further use (t24). Conjunctival swabs were taken before and after drop applications to evaluate contamination sources.
Of the 110 eyes evaluated, 8.1% of drops were contaminated at t0, 11.8% at t10, and 10.0% at t24. Contamination was more frequently attributed to fingertip flora rather than ocular surface flora. In 5 of 21 cases of contaminated drops, the same bacterial species were identified in both the drop and the initial conjunctival swab.
The researchers suggest that the reuse of these eye drops may be safe within this timeframe, potentially reducing medical waste and associated costs.
The authors reported no potential conflicts of interest.