Eyeworld

EW NEWS & OPINION September 2016 29 eyesight to allow us to recognize a potential surgical complication. "Every HORV event associated with vancomycin was with vanco- mycin mixed in the facility by staff or from uncertain manufacturing sources with OR dilution required, noting that none was created in a ready-made unit dose via 503A/B manufacturing. Is it actually the vancomycin drug or perhaps some sort of operating room contamina- tion coupled with vancomycin? "I've heard one in 3,000,000 as an occurrence rate for HORV; one in 3 million or one in 1 million is still debatable, but both are very low incidence. Endophthalmitis is 2,500 in a million with eye drops and povidone, 400 in a million with intracameral antibiotics, and 10 in a million with intravitreal antibiot- ics (specifically Tri-Moxi/Tri-Moxi- Vanc). Eighty-five percent of these infections are Staphylococcus aureus. MRSA is reaching 50% of colonies cultured in American hospitals (well above 50% in urban and suburban locations). Vancomycin is the only agent that will effectively protect against MRSA. High dose moxifloxa- cin will not suppress MRSA. "My conclusion is the risk of vancomycin-induced HORV is trivial compared to the risk of MRSA en- dophthalmitis. It is the bilateral po- tential of vancomycin sensitization and HORV that is most disruptive. "Doctors who have used moxi- floxacin (or a related agent) and got- ten an MRSA endophthalmitis will recognize the risk/benefit ratio of either threat and adjust their surgi- cal decision-making to better match their risk analysis. Likewise, the surgeons who have experienced the catastrophic HORV have adjusted their risk-taking based on their per- sonal experiences. Other surgeons like us listen to both groups and make our own conclusions that we then bring into the OR. I'm not sure there is a universal right or wrong answer. Best judgment requires data and informed analysis. "I continue to use Tri-Moxi- Vanc on all my patients. I am a consultant for Imprimis." Dr. Witkin responded, "Re- garding skin testing, four of 22 patients had negative skin testing to vancomycin. According to our consultation with allergists, skin testing is unlikely to be helpful in type III hypersensitivity. In general, diagnosis of type III hypersensitivity reactions is mostly based on clinical history and sometimes histology if available. "Regarding a possible contam- inant, this is unlikely for a few rea- sons. First, some patients had HORV in one eye, and waited months or years (up to 9 years) until the second cataract surgery was performed, but once they had surgery in the second eye, the second eye also developed HORV. Second, there was one case that had one eye cataract surgery with vancomycin that developed HORV, and the second eye surgery without vancomycin that had a normal postoperative course. Third, in TASS, often cases occur in clusters if there is a contaminant in the ma- chinery or a defect in the autoclave or facility. This has not occurred in HORV. "Regarding incidence, I think it is difficult to tell at this time. It is likely very rare, but there have been a number of cases reported to us that were previously misdiagnosed as endophthalmitis or CRVO. Also, there have been mild cases that were asymptomatic, which suggests that we may only be aware of the most severe cases of HORV, and there may be a number of milder unreported cases. At this time, I would hesitate to definitively give a number for the incidence of HORV until more infor- mation is known about these mild cases and until there has been more time for people to become aware of this disease. "I think the argument can be made to use vancomycin over other antibiotics to prevent certain drug-resistant types of endoph- thalmitis. However, the incidence of bacterial endophthalmitis that would only be treatable with van- comycin is low. I would argue that in close sequential bilateral cataract surgery, the risk of both eyes going blind from HORV may outweigh the risk of one eye going blind from bac- terial endophthalmitis from MRSA or other moxifloxacin-resistant (or cefuroxime-resistant) bacteria." EW Contact information Akler: michelle@aklereye.com Chang: dceye@earthlink.net Jumper: jmichaeljumper@gmail.com Witkin: AWitkin@tuftsmedicalcenter.org AMOILS Minimize total procedure time Avoid alcohol damage to surrounding tissue No need for subsequent scraping Uniform epithelium removal in only 5 - 7 seconds Improved clinical outcomes of CXL and PRK with T. 800.461.1200 www.innovativexcimer.com e time scra r ping mes m COME VISIT US AT CHICAGO, USA 2016 OCT 15-18 BOOTH #4244 AAO

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