IPoster: Bacterial and Pharmacological Stability of Diagnostic Eye Drops

Purpose: Eye care professionals use diagnostic eye drops on a daily basis for their anesthetic, mydriatic and cycloplegic effects. Once opened, pharmaceutical companies recommend discarding ophthalmic drugs after 28 days. However, this recommendation applies to patients who self-administrate their prescribed eye drops in a home setting. The aim of this study was to evaluate the preservation period and the efficacy of ophthalmic preparations, such as Alcaine®, Mydriacyl®, Mydfrin® and Cyclogyl® in a clinical and controlled setting.

Methods: 38 primary eye care students were recruited to participate in the study. They used 25 bottles of each diagnostic drop at the “Clinique Universitaire de la Vision” for a 7-month period. An analysis of the bacterial contamination was repeated ten times using both an agar plate and a nutrient broth, at time 0, 2, 4, 6, 8 weeks and 3, 4, 5, 6, 7 months. The anesthetic (Alcaine®), mydriatic (Mydriacyl®, Mydfrin®) and cycloplegic (Cyclogyl®) effects were tested after seven months of use and compared to non-opened ophthalmic bottles.

Results: During this period, 4971 drops of Alcaine®, 3219 drops of Mydriacyl® and Mydfrin® and 1896 drops of Cyclogyl® were administered to patients. Contact between bottles and biological tissues were reported 80 times for Alcaine®, 53 times for Mydriacyl®, 38 times for Mydfrin® and 52 times for Cyclogyl®. Following the 10 inoculation sessions on the agar medium at the predetermined times, no bacterial and fungus contamination was noted. No patient reported eye infections between two weeks following drop instillation. Moreover, there was no difference in the efficacy when compared with new drops.

Conclusion(s): According to the results of the current study, diagnostic eye drops can be used with a low contamination risk beyond the recommendation date of 28 days up to 7 months, with the same efficacy, in a controlled clinical context.

Jean-Marie Hanssens, OD, PhD

Assistant Professor, Université de Montréal

Jean-Marie Hanssens is an assistant professor at the Universite de Montreal. Its research activities are concentrated around ophthalmic optics and progressive lenses.  In addition to his research activities, he held the position of clinic director and residency program director. 

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