EyeWorld Asia-Pacific June 2017 Issue

June 2017 EWAP SECONDARY FEATURE 37 to treat what was thought at the time to be endophthalmitis and five of the seven ended up with no light perception. Dr. Mamalis said that the majority of HORV patients also experienced a mild to moderate anterior chamber reaction, though not as severe as seen with TASS, in addition to mild to moderate vitritis. The hallmark of these patients, however, is a hemorrhagic occlusive vasculitis seen in a dilated fundus exam of the retina. The retinal vasculitis seems to preferentially involve the peripheral venules, Dr. Chang observed. “There are large sectoral hemorrhages in the affected ischemic areas of retina. Diffuse blot hemorrhages, and vascular dilation and tortuosity are seen with CRVO but not HORV,” Dr. Chang said, adding that early progression to neovascular glaucoma is unfortunately common with this condition. Of the 36 eyes in the latest published series that were diagnosed with HORV after receiving vancomycin intracamerally, intravitreally, or in the irrigation bottle, 61% (22/36) were 20/200 or worse, and 22% (8/36) had no light perception. “We have yet to identify a single case of confirmed HORV that did not receive vancomycin. In addition, there were multiple sources of vancomycin used in these cases, which suggests that it is the drug rather than an adjuvant associated with a particular manufacturer or batch,” Dr. Chang said. Immunologists consulted by the ASCRS/ASRS task force said the delayed response after vancomycin administration is consistent with a Type III hypersensitivity reaction. “This is a delayed hypersensitivity reaction in which antigen-antibody immune complexes are deposited into tissues such as vascular walls where they incite severe inflammation through activation of the complement cascade. Type III reactions often preferentially involve the venules and would be more severe upon repeat antigen exposure,” Dr. Chang said. Intravenous vancomycin has previously been implicated as causing Type III hypersensitivity reactions, such as leukocytoclastic vasculitis. 4–6 Treatment Dr. Miller said physicians first need to rule out other conditions that could look like HORV, such as viral retinitis, endophthalmitis, or CRVO. While it’s too late to reverse the damage that has already occurred, treatment upon diagnosis of HORV is all about downstream damage control, he said. “We’re talking about using high-dose systemic and topical corticosteroids,” Dr. Mamalis said. “We want to do everything we can to decrease the inflammatory response and to limit it. People may even want to consider intravitreal corticosteroids because that’s where you get a high dose of corticosteroids into the eye where this reaction is occurring.” In fact, three eyes in the most recently published study received intravitreal dexamethasone implants upon presentation with HORV and ended up seeing 20/40, 20/70, and hand movements, respectively. “It’s possible that the intravitreal steroids may be targeting the inflammation in the eye, specifically,” Dr. Witkin explained. Because patients with HORV often go on to develop neovascular glaucoma, due to the severity of ischemia in the retina, early intervention with anti-vascular endothelial growth factor treatments and panretinal laser photocoagulation treatment are recommended as well. Prevention Antibiotic prophylaxis became more widespread after the European Society of Cataract and Refractive Surgeons published a 2007 paper that found a reduced rate of postoperative endophthalmitis with use of intracameral cefuroxime. 7 A 2014 ASCRS survey confirmed increasing use of intracameral antibiotics among membership, usually in conjunction with topical perioperative antibiotics. 8 At that time, vancomycin was used by 37% of the respondents who administered intraocular antibiotics. According to a survey of 556 domestic ASCRS members conducted in 2016 ahead of the ASCRS/ASRS HORV clinical alert, 22.1% of all survey respondents used vancomycin during cataract surgery. 9 Without a commercially available, U.S. Food and Drug Administration-approved antibiotic formulation for use in the eye, Dr. Witkin said vancomycin is among the easiest to formulate. “People have a lot of comfort with it; it has a very broad coverage of gram- positive microorganisms and had previously been used in ophthalmology for many years without any reported issues,” he said. But with even a small risk for HORV, should vancomycin be used intracamerally? Recommendations put forth by the ASCRS/ASRS clinical alert include each surgeon “[weighing] the potential risk of HORV associated with vancomycin against the risk of endophthalmitis.” If a physician determines the risk for endophthalmitis without an intracameral antibiotic is more than the risk of TASS or HORV with one, Dr. Miller said a preventative measure could involve the surgical schedule. “One thing surgeons should consider if they’re going to use vancomycin and they’re staging these things close together—some of these things don’t show up until 3 weeks after surgery … for anybody that’s contemplating using vancomycin, they should probably be separating their surgery by 4 weeks or more, and making sure the patient is asymptomatic in the first eye before they move onto the second eye,” Dr. Miller said. What’s next Michael Teske, MD , The Eye Institute, Salt Lake City, at the continued on page 38