Moxifloxacin 0.5% (Vigamox®, Alcon, Texas) was drawn up undiluted for the 0.05 mL and 0.1 mL injection volume test groups. For the 0.15% diluted solution, 2 mL Vigamox® was mixed with 4.66 mL balanced salt solution (BSS®, Alcon) to produce the final concentration (1.5 mg/mL or 1,500 µg/mL) to be used for the 0.50 mL injection volume test group (flushing method). An experienced ophthalmic operating room technician drew up 5 aliquots of drug in 1 mL syringes (305780, BD, New Jersey) with an 18-gauge needle for each of the 3 test groups (total of 15 syringes). The needle was replaced with a 27-gauge cannula (K20–3101, Advena, UK) and following a visual inspection to ensure the absence of air bubbles, the technician pushed the excess drug solution through the cannula to the starting point for the test group.
Under an operating microscope, the study ophthalmologist (NS) completely ejected the syringe contents into an open, previously tared, 1.25 dram glass vial. Each glass vial was capped, handled with gloved hands throughout the study, and was randomly weighed on a digital scale (Adventurer Pro®, Ohaus, New Jersey), following zeroing, reading to the nearest milligram. Drug doses (µg) were calculated by multiplying the mass of the delivered solution by the concentration of drug.
Under an operating microscope, the study ophthalmologist (NS) completely ejected the syringe contents into an open, previously tared, 1.25 dram glass vial. Each glass vial was capped, handled with gloved hands throughout the study, and was randomly weighed on a digital scale (Adventurer Pro®, Ohaus, New Jersey), following zeroing, reading to the nearest milligram. Drug doses (µg) were calculated by multiplying the mass of the delivered solution by the concentration of drug.