Eyeworld

EW CORNEA 112 March 2018 by Rich Daly EyeWorld Contributing Writer patients first with natamycin, which is the only commercially available antifungal treatment in the U.S. In candida patients, which are more common in the northeast U.S., Dr. Amescua uses topical am- photericin B drops. Performing therapeutic keratoplasty The decision to move from medical therapy to a keratoplasty is done on a case by case basis, Dr. Amescua said. Therapeutic grafts are consid- ered in cases of corneal perforations or impending perforations. When the ulcer is central and not improv- ing after weeks of antifungals and the tissue starts melting, a thera- peutic penetrating or lamellar graft should be performed to avoid a perforation. "Doing a corneal transplant in an eye that is inflamed where we can't use steroids shortly after surgery because of the possibility that there could still be some fungal elements decreases the prognosis of the transplant," Dr. Amescua said. Therefore, early and aggres- sive treatment is needed in fugal keratitis. "We need to do everything possible to cure the infection, stop the inflammation if a scar is present, and later proceed with a lamellar or penetrating optical graft," he said. Publications from Asia have shown that corneal surgery earlier available and FDA-approved for ocular infections, was previously thought to be the best treatment for patients who had filamentous fungi such as Fusarium, Dr. Mah said. Yeast and candida would be better treated with amphotericin B, which in the U.S. is off-label and an extempora- neously mixed drug. "Fungi have a much higher propensity for becoming resistant on one agent," Dr. Mah said. "One of the keys is to treat with two dif- ferent classes of antifungals so that the development of resistance is reduced, and even if it does become resistant to one agent, you have the second agent there." New evidence on treatments emerged over the last several years from the results of the Mycotic Ulcer Treatment Trial (MUTT), which was a randomized compari- son of natamycin and voriconazole. Voriconazole, a newer antifungal agent, has a reduced minimum in- hibitory concentration (MIC) and is more potent than natamycin. "Natamycin still has excel- lent coverage of the filamentous fungi so even with the addition of voriconazole to our armamentari- um, natamycin still seems to have excellent coverage, and patients did better on natamycin," Dr. Mah said. Filamentous fungi are the most common Dr. Amescua sees in his area of practice. Based on the MUTT results, he treats filamentous Latest approaches to fungal infections I t's November in Toronto, Canada, and a fresh coat of snow had come down the night before. I am seeing a new patient referred for a non-healing paracentral 2 mm corneal ulcer that was "culture positive for Staph epidermidis." The patient had already been using fortified antibiotics for a month prior with minimal improvement. Why was the corneal infiltrate not clearing? Was it related to topical medication toxicity? Was it related to the Herpes simplex virus since he does get frequent cold sores? With some prodding, he recounted that he had been chopping wood at his weekend lake house a couple months before and had gone swimming on an uncharacteristically balmy September day with his contact lenses in the day before he awoke with eye pain. I had just returned from the Amer- ican Academy of Ophthalmology annual meeting, and some cornea colleagues from the Midwest and Eastern United States had commented that they had noticed an increase in fungal corneal infections in their practices located in areas where fungal infections were extremely rare. In the past few months, they had treated a few patients with a small corneal infiltrate that typically would be adequately treated with a fluoroquinolone but ended up being a fungal infection. With this recent conversa- tion in mind, I suggested to my patient that we should reculture his corneal infiltrate specifically to inquire about the presence of any fungal organisms. Within a few days, I received the dreaded call that the cultures were positive for Aspergillus, and we initiated treatment immediately. I wanted to share my anecdote and give EyeWorld readers the opportunity to learn from the experts. In this month's "Cornea editor's corner of the world," Guillermo Amescua, MD, and Francis Mah, MD, discuss pearls for the diagnosis and management of fungal corneal ulcers. Clara Chan, MD, Cornea editor Amid concerns that fungal infections may be increasing, ophthalmologists highlight keys to their detection and treatment A lthough generally rare, fungal infections are more likely in certain pa- tients and require a close watch to detect and treat. Guillermo Amescua, MD, Bascom Palmer Eye Institute, Miami, has seen a slight increase in fungal infections among his patients in the humid south Florida region. "Fungal ulcers represent about 25–30% of all the cases of keratitis we see at Bascom Palmer. What we have seen is an increase in the num- ber of fungal infections post-lamel- lar corneal transplant, patients who have had DSEK or DMEK, and those are very challenging to treat," Dr. Amescua said. Dr. Amescua thinks the increase may be a result of the significant in- crease in the number of endothelial keratoplasties being performed and the lack of antifungals in the pres- ervation solution used to transfer grafts over concerns they are toxic to the cornea. Vulnerable eyes Eyes with herpes keratitis infections generally are at increased risk for any type of super infection, mean- ing a second pathogen like bacteria, fungus, or a parasite, said Francis Mah, MD, director of cornea and external disease, and co-director of refractive surgery, Scripps Clinic, La Jolla, California. "Those eyes in general have nerves that are not as sensitive," Dr. Mah said. "Those patients have neurotropic keratopathy so the sen- sitivity is a little down and they may not be as alert." Herpes patients are also more prone to surface issues, whether it is keratitis because of the neuropathy or chronic epithelial defects. Additionally, many herpetic patients are on anti-inflammatories, like steroids. Such medication can lower the local immune system. First line treatments Natamycin, which is commercially A 36-year-old male with a history of wearing soft contact lenses was referred for treatment of rapidly progressive infectious keratitis not responding to medical treatment. The patient reported severe ocular pain and redness on the left eye for 2 weeks. Source: Guillermo Amescua, MD, and Jaime Martinez, MD Cornea editor's corner of the world

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