How to Select the Most Effective Antibiotic to Prevent Infection in Cataract and Refractive Surgery

Richard L. Abbott, M.D.
Thomas W. Boyden Health Sciences Professor of Clinical Ophthalmology
Beckman Vision Center
University of California San Francisco
Research Associate
Francis I. Proctor Foundation

The issue regarding the most effective prophylaxis to decrease the risk of infection following cataract and refractive surgery has been studied and debated for many years.  In addition to careful pre-operative examination of the lids and conjunctiva to assure there is no active infection present, as well as the use of peri-operative povidone iodine antiseptic applied to the lids and ocular surface just prior to surgery, the use of newer- generation topical fluoroquinolones (Levofloxacin, Gatifloxacin, and Moxifolxacin) both pre and post-operatively have provided ophthalmologists with the most effective antibiotic coverage to date. 

Selecting which fluoroquinolone to use should be based not only on its overall effectiveness in preventing infection, but also on its ability to not cause toxicity to the cornea and surrounding structures.  The potency and broad range of coverage of the fluoroquinolone antibiotic, as well as its ability to reach high concentration levels in the ocular tissues help prevent resistant organisms from forming.   A balance must be achieved when choosing the most effective fluoroquinolone to use, since wound healing and corneal surface stability are extremely important to maintain in post-operative LASIK and cataract surgery patients.  In a recent study performed by Professor Choun-Ki Joo at The Catholic University of Korea, a comparison between non-preserved Levofloxacin (Cravit) and non-preserved Moxifloxacin (Vigamox) was made regarding their effect on the corneal endothelium and on corneal epithelial wound healing.  These studies clearly demonstrated that Levofloxacin (Cravit) as compared to Moxifloxacin (Vigamox) had less toxicity to the cornea and did not interfere with wound healing. 

In reviewing the many in-vivo and in-vitro studies that have been completed over the past several years and carefully examining the data from these studies, it is evident that Levofloxacin meets the criteria for being a highly effective fluoroquinolone antibiotic to prevent infection, as well as demonstrating the least toxicity to the ocular tissues.   Data from the ongoing TRUST (Tracking Resistance in the US Today) studies clearly show that, over a ten year period, the clinical effectives of the newer-generation fluoroquinolones against the most clinically important Gram positive and Gram negative organisms are equivalent in killing the organisms and preventing resistance from occurring. In addition, these newer-generation flouroquinlones all have similar dual mechanisms of action in killing the bacteria by acting on two separate sites of the bacterial DNA. Finally, all of the newer-generation fluoroquinolones (Levofloxacin, Gatifloxacin, and Moxifloxacin) are considered to be in the same generation classification according to the systemic infectious disease literature. 

In summary, preventing resistance from occurring with these virulent organisms is extremely important as we look ahead in the continuing fight to prevent infection in our post-operative patients. Using the higher concentration fluoroquinlones (0.5%) and using a dosing level that never drops below the four times a day regimen is very important to meet this goal. When using the fluroquinolones, the dose should never be tapered below four times a day and the course of the treatment generally should not be longer than two(2) weeks. In choosing the ideal fluoroquinlone, it should have all of the following  properties:  Broad spectrum of coverage, excellent penetration into the tissues, excellent drug solubility, rapid onset of action, low toxicity, low resistance especially with Gram positive organisms, and it should be compatible with other drugs.  The newer-generation flouroquinolones meet these criteria…with Levofloxacin (Cravit) having the advantage with the least toxicity to the cornea and the least interference with wound healing.

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