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Vy-Vy Ngo, Gloria Wu, Laura Billard, Amy Doan, Bryan Le, Elena Muro; Heidelberg Spectralis Infrared Imaging and Measurement of eye medication nozzle size and flow. Invest. Ophthalmol. Vis. Sci. 2018;59(9):4690. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the common eye medications and their ability to dispense eyedrops.
We selected common eye medication(eyemed) samples in an ophthalmic office. 27 medications: Paragon Phenylephrine, Akorn Proparacaine, Sandoz Timolol, Valeant Timolol, Sandoz Prednisolone, Clear Eyes, Akorn Timolol, Rising Timolol, B+L Proparacaine,B+L Tropicamide (2ml), B+L Tropicamide (15ml), B+L Gentamicin, Sandoz Brimonidine, Sandoz Tropicamide. For the Branded: Systane Ultra, Systane Balance, Systane Gel, Blink Gel Tears, Refresh Gel Drops, Alcon Cyclogyl 1%, Alcon Durezol, Allergan Combigan, B+L Bepreve, and Allergan Alphagan, B+L Lotemax, Alcon Simbrinza, Nanotears.Using the Heidelberg Spectralis (Heidelberg, Germany) infared imaging, we measured the diameter of the dispensing hole in the nozzle of eyemeds. We controlled magnification by using the focal distance (22 cm), resolution =5 diopters, light intensity =100%, 30 degree field of view. The inferior margin of the eye dropper tip was lined up to the top line of the lateral canthus indicator of the Heidelberg Spectralis head rest. A mm ruler was imaged at the same time at the same magnification.To evaluate the ease of flow, the eye meds were lined up at 180 degrees and 90 degrees, each timed for one second for flow. In addition, we videotaped and timed the release one eyedrop when a metal clamp was applied to the body of the eye medication, yielding "drop/time."
Branded eye meds v Generics: nozzle opening (mm)=(avg 2.01 sd=0.49 v avg1.27mm sd=0.24)with branded medications having a larger diameter opening (p=0.02).At 180 degree positioning, none of the dropper bottles allowed flow.Of the 24 eye drop medications tested, there were 9 that released one drop when held at 90 degrees (upside down) for one second.Evaluating the time of release of one eyedrop (drop/time): n=22 (non gel eyedrops): Generic drop/time(avg 1.49 sec sd=1.00 )vs Brand drop/time (avg 2.75 sec sd=1.40 ) (p=0.0235).
This small study suggest that nozzle opening sizes are different and consistent flow of eyedrops may be problematic among the different manufacturers and brands. The plastic casing of the eye medications vary among the medications tested. In the future, eye medication bottles could be evaluated and tested for a standard opening diameter size and uniform compressibility for consistent delivery of dose volume.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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