Eyeworld

EW CORNEA 56 July 2015 by Maxine Lipner EyeWorld Senior Contributing Writer have it in your mind, is one of the biggest saviors," he said. Likewise, Elmer Tu, MD, pro- fessor of clinical ophthalmology, University of Illinois, Chicago, finds that fungal infections tend to be less immediately aggressive than their bacterial counterparts. The best way to diagnose them is to culture them, Dr. Tu stressed. However, there can be challenges in getting samples of fungal keratitis, which can be very deep and difficult to reach. In addi- tion, while some fungus will grow out in culture within just a few days, others may take 3–4 weeks. Use of confocal microscopy, in conjunction with the appearance of the cornea, can suggest fungal keratitis as early as the first office visit, Dr. Tu noted. Determining whether you are dealing with filamentous or non-fila- mentous fungi is likewise important. "When we talk about non-filamen- tous (fungi), it's going to be Candi- da," Dr. Tu said, adding that only occasionally will you see another yeast such as Cryptococcus instead. Such infections have a tendency to be a bit easier to treat, and they're usually slightly more sensitive to particular antifungals than the fila- mentous fungi, he said. Dr. Mah pointed out that Can- dida infections are likely to occur in more temperate climates. "So, for example, in the United States they're probably going to be found in the majority of sites, whereas the classic filamentous fungi are found in humid, hot climates," Dr. Mah said. In general he finds that filamentous fungi do cause more sequelae and more morbidity than Candida. Treatment alternatives "In general, Candida responds well to amphotericin and to a lot of different treatments including natamycin and fluconazole," he said. For filamentous infections, he finds that natamycin can also be a good medication. In addition, am- photericin works well, even though the books say that it is not supposed to, Dr. Mah said. Dr. Tu finds that when dealing with a fungal infection, natamycin, which is the only commercially available antifungal agent in the United States, is usually an excellent medication to start with, particularly for filamentous fungi. However, in cases where practitioners are sure that they're dealing with Candida, other agents such as topical ampho- tericin B or voriconazole tend to be more effective, he said. Recent evidence shows that the use of oral agents can also prove helpful. "The evidence prior to recent years has been pretty thin in terms of the beneficial effects of oral therapies," Dr. Tu said. "But our group and others have shown that the addition of the newer oral agents can have significant penetration into the eye and into the cornea to help with the treatment of these infections." With the aid of oral voriconazole and oral posaconazole, Dr. Tu has been able to cure some fungal corneal infection cases with- out the need for surgical treatment. "The evidence is both in studies but also clinically that these newer drugs do have enough intraocular penetra- tion to reach levels that can eradi- cate the infection," Dr. Tu said. Dr. Mah agrees that oral agents can play an important role. "One of the problems in treating fungal infections is that fungi become resistant a lot faster than bacteria do," he said, adding that in general physicians should use 2 different therapies here. So, particularly if it is a serious infection, Dr. Mah will use both topical amphotericin B and natamycin and then also oral medications such as fluconazole, itraconazole, or ketoconazole. Other approaches may also be helpful. Dr. Mah pointed out that to Finessing fungal infections T he incidence of fungal keratitis can vary by geography and ranges from 2% of keratitis cases in New York to 35% in Florida. A clinician's greatest fear is if the fungal organisms extend beyond the cornea leading to severe complications of scleritis, endophthalmitis, or panophthal- mitis. Since fungal infections are usually more difficult to treat, they may result in severe visual loss or even loss of the eye. Unfortunately, a delay in the diagnosis is common, mainly due to a lack of suspicion. Isolation of the organism from cultures can also be challenging. Even with a confirmed diagnosis, antifungal agents have poor corneal penetration. This month's "Cornea editor's corner of the world" focuses on how to recognize fungal corneal infections and treatment op- tions. Francis Mah, MD, and Elmer Tu, MD, discuss their experiences with managing fungal keratitis and provide pearls for an earlier diagnosis. Clara C. Chan, MD, FRCSC, FACS, cornea editor Examples of fungal keratitis Source: Francis S. Mah, MD Cornea editor's corner of the world Considering the latest treatments D epending upon where a patient lives or perhaps has recently traveled, fun- gal infections may need to be on practitioners' radar. Fungal infections are a lot more common in a hot, humid environ- ment or in agricultural type situa- tions, said Francis Mah, MD, direc- tor of cornea and external disease, and co-director of refractive surgery, Scripps Clinic, La Jolla, Calif. In the United States, particularly in places such as Florida and Texas, practi- tioners need to have a high index of suspicion that a fungal infection is a possibility, he said. As a rule, fungal infections tend to be indolent, Dr. Mah finds. "They seem to get deeper rather than broader," he said. "The body doesn't react quite as violently for whatever reason and because of that they may get dismissed as not being so serious." Is it fungal? To help determine if the infection is fungal in nature, he recommended taking a thorough history. Practi- tioners should hone in on whether the patient was traveling or was in some other environment ripe for fungal infections. "I think just mak- ing sure that it's in your differential diagnosis every single time, just to

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