Publication Exclusive: Intraocular antibiotic prophylaxis in best interests of patients

During my residency and fellowship training in the 1970s, the two most dreaded complications of cataract surgery were expulsive choroidal hemorrhage and endophthalmitis. In advanced countries, expulsive choroidal hemorrhage has been nearly eliminated as a blinding complication by phacoemulsification with its small self-sealing incision. The incidence of infectious endophthalmitis has been reduced from as many as one per 400 during my training to about one per 1,000 through the use of povidone-iodine antiseptic prophylaxis, careful draping of lids and lashes, and surgeon care in assuring a well-sealed incision, but there is still room for improvement in preventing this serious sight-threatening complication.

In the U.S., topical antibiotics are used nearly routinely, started a few hours to days before the surgery, given again in the operating room immediately after surgery and then continued for 1 or more weeks, depending on the surgeon. Unfortunately, data to support the use of topical antibiotics in an advanced country operating suite where povidone-iodine prep and good draping are utilized are lacking. Nonetheless, more than $500 million worth of off-label antibiotic drops (because the antibiotic drops utilized are only approved by the FDA for the treatment of bacterial conjunctivitis or keratitis) are prescribed each year in the U.S. and universally reimbursed by third-party payers, including CMS, for endophthalmitis prophylaxis.

If one examines the literature in other surgical specialties regarding antibiotic use for infection prophylaxis, the critical elements are a high concentration of a bactericidal antibiotic effective against the most likely infectious agents given perioperatively in the operating suite that reaches therapeutic concentrations in the target tissue or space. For ophthalmology, the infectious agents are primarily gram-positive staphylococcal and streptococcal species, many of which may express some level of methicillin resistance. The tissue or space is the anterior chamber and vitreous. The antibiotics most commonly selected for infectious prophylaxis in ophthalmology by those expert in the field include vancomycin, a so-called fourth-generation fluoroquinolone, cefuroxime or tobramycin, alone or in combination.

While reduction of surface pathogen load with preoperative antibiotic drops is of potential value, there is no good supporting literature for this approach, and the povidone-iodine antisepsis now routinely placed onto the ocular surface and into the conjunctival fornices puts the value of this approach in question.

The target perioperative area for the eye is intraocular contamination of the anterior chamber and vitreous with surface pathogens during surgery. This naturally led cataract surgeons to consider intraocular antibiotics at the time of surgery. Following the lead of Jim Gills, MD, and others, nearly 20 years ago I adopted vancomycin and tobramycin placed in the irrigating bottle and delivered during surgery. My clinical experience, and that from other surgeons, suggested this was an effective approach, but laboratory studies suggested that the antibiotic concentrations achieved were subtherapeutic. The next approach evaluated by pioneering surgeons was to inject antibiotics directly into the anterior chamber and later into the vitreous following the completion of surgery. Laboratory studies confirmed that an effective antibiotic concentration could be reached using this method. In addition, studies confirmed effective doses of the preferred antibiotics could be used safely without damaging the corneal or trabecular meshwork endothelium or retina. Fortunately, effective bactericidal concentrations of several antibiotic drugs were found to be safe according to laboratory and clinical studies. This led a significant number of the world’s ophthalmologists to adopt the clinical application of intraocular antibiotics for prophylaxis against infectious endophthalmitis.

Click here to read the full publication exclusive, Lindstrom's Perspective, published in Ocular Surgery News U.S. Edition, July 25, 2016.