We appreciate the comments from Drs Fiscella and Jensen. The dual-biopsy technique is an optimal method for assessing conjunctival anti-infective concentrations. And, we strongly agree that additional factors should also be considered when evaluating drug efficacy.
Conjunctival drug levels are of particular importance in bacterial conjunctivitis because the conjunctiva is the tissue to which the bacteria adhere—the site of infection. This, of course, is not a difficult concept. We disagree that the formulation concentration differences between 0.5% moxifloxacin and 0.3% gatifloxacin resulted in the difference in conjunctival concentration. In fact, 0.5% levofloxacin had a lower mean conjunctival concentration (2.34 μg/g) than 0.3% gatifloxacin (2.54 μg/g).
Wagner RS. Evaluation of the Penetration of Fluoroquinolones in Human Conjunctival Tissue—Reply. Arch Ophthalmol. 2006;124(12):1797. doi:10.1001/archopht.124.12.1797-a