The Rationale For Lower Concentration Intracameral Moxifloxacin For Post Operative Endophthalmitis Prophylaxis In All Cases

To calculate an optimal dose and administration method for prophylaxis of post operative endophthalmitis (POE) with intracameral moxifloxacin (ICM) for different circumstances.

York Finch Eye Associates and The University of Toronto

We recently reported a mathematical model to determine the optimal dose and delivery technique of ICM for routine phaco surgery. Haripriya at al. and Kerrison et al. have concurred in two very large series that the risk of POE is higher in cases of posterior capsular rupture (PCR) and secondary IOL implantation. We used our mathematical model to discern the differences induced by these complications and to determine a dose and administration method for ICM in routine and PCR cases, with the intention of devising a simple effective method for all scenarios

PCR changes the volume considerations for ICM administration. In such cases, one would logically tend to increase the concentration of ICM to achieve the bactericidal concentration for POE pathogens (500 µg per 0.5 mL), while trying to minimize the risk of drug toxicity. Dilute moxifloxacin offers the counterintuitive benefit that because of the larger volume injected (compared to a more concentrated solution), mixing model methodology demonstrates that more is retained in the eye, proportional to the volume of the “effective anterior chamber” being treated, and has less potential toxicity.

The routine ICM concentration of 150 µg/0.1 mL. offers the counterintuitive benefit of leaving more drug in the "effective anterior chamber" in the absence of a posterior capsule without increasing the risk of toxicity when the dose is increased from 0.55 to 0.70 mL. The increased volume remains safe for routine cases, but enhances anti-infective protection for PCR and secondary IOL cases. The precise methodology, results and cautions will be presented.