To determine the amount of moxifloxacin remaining in the anterior chamber (AC), immediately after its injection using 3 current injection methods, assuming mixing and fluid exchange with the AC contents during injection of the drug, and to determine the most desirable injection method. Department of Ophthalmology and Vision Sciences and Institute of Biomedical Engineering, University of Toronto, Toronto, Canada. Mathematical modeling. Mathematical modeling using first-order mixing methods were used to assess mixing. The Kaiser method of injecting 0.5 mL × 100 μg/0.1 mL does not achieve the desired 500 μg level of moxifloxacin in the AC. The "straight from the bottle" method of injecting 0.1 mL × 500 μg/0.1 mL is fraught with potential error, yielding a relatively unreliable final amount in the AC. Injecting 0.5 to 0.6 mL × 150 μg/0.1 mL yields a result closest to the desired goal. Based on the calculation, the most accurate of current methods to deliver 500 μg moxifloxacin intracamerally is the method of 150 μg/0.1 mL × 0.5 to 0.6 mL.