This study is being conducted to assess the concentration of besifloxacin, moxifloxacin, or gatifloxacin in aqueous humor samples collected following topical instillation of the associated formulation in subjects undergoing cataract surgery.

Inclusion Criteria:

• Subjects who are a candidate for a routine, uncomplicated, primary cataract extraction.
• Subjects who, in the Investigator's opinion, have potential for postoperative best corrected Snellen visual acuity of at least 20/200 in the study eye.

Exclusion Criteria:

• Subjects who have a known sensitivity, contraindication, or allergy to the study medication(s) or their components.
• Subjects who had any corneal refractive surgery in the study eye.
• Subjects who have a history or presence of chronic generalized systemic disease that the Investigator feels might increase the risk to the subject or confound the result of the study.
• Subjects who had ocular surgery in the study eye, including laser procedures, within the past 6 months.
• Subjects who have taken any topical ocular medication in the study eye, other than those required by the protocol and permitted for surgery, during the 24 hours prior to the study medication being instilled.
• Subjects who use any antibiotics (e.g., systemic or topical) within the 7 days prior to the surgery date.
• Subjects who are monocular.

Single ocular administration

All drug concentrations were significantly below MIC90 values for relevant staphylococcal species.