51 EyeWorld Asia-Pacific | September 2024 CORNEA epithelial keratitis) that are visualized on exam or geographic epithelial keratitis, typically you need to start these patients right away on antiviral therapy. In terms of topical treatment, he also mentioned that it can result in epithelial toxicity. The two topical options currently available are trifluridine (which is more toxic) and a ganciclovir gel (less toxic but not always covered by insurance and often requires pre-authorization). Oral antiviral medication are usually as effective, he said, and they’re typically easier to get covered by insurance, but they may need potential adjustments in the dose depending on the patient’s kidney status. “I think generally speaking, most practitioners use topical treatments, but others, including myself, prefer oral therapy because of the potential high efficacy, the coverage of insurance, lower chance of toxicity, and better compliance,” Dr. Hamrah said. “The frequency of oral therapy is also less than topical drugs.” If the patient develops a recurrence, oral treatment is recommended per the Herpetic Eye Disease Study for a year and a half, as this has been shown to decrease the recurrence rate by 70%, but it is not safe to keep patients on topical antivirals for this long. Topical therapy should thus only be used in the acute settings, while oral antivirals can be used chronically, he said. In very severe cases, Dr. Hamrah said both topical and oral antivirals can be used concurrently. For non-epithelial herpetic flare-ups, some physicians still use oral antivirals as well, in order to prevent stromal keratitis or scleritis. Anti-inflammatory therapies can work well, but sometimes the virus may cause persistent inflammation, and unless treated with oral antivirals, the condition does not resolve. How quickly do the treatments work? “In an acute setting, usually 7–10 days are sufficient in most cases,” Dr. Hamrah said. However, he noted that there are always exceptions — for example, if the patient is immunosuppressed. Patients who have atopic disease or autoimmune disease respond differently, so it depends on the comorbidities. These treatments should also work for patients with persistent herpetic keratitis. But we have seen cases where patients might be resistant to the treatments, Dr. Hamrah said, adding that if they don’t respond, the accuracy of the diagnosis should be reconsidered. Many times, patients with Acanthamoeba keratitis or fungal keratitis can be misdiagnosed as herpetic keratitis. Dr. Raju explained that how quickly the treatment works varies between epithelial and stromal keratitis. With epithelial, if you’re doing a topical preparation, you usually see response in a couple of days, which is why she also thinks the course does not have to be as long as originally prescribed for some. With stromal, it’s not only going to be reducing any viral shedding that’s going on, “it’s also going to reduce the swelling that’s in the cornea, so that often requires topical steroids as well,” Dr. Raju said. “Sometimes it requires a very slow taper on the steroid. You’ll start seeing a response in the first week to 2 weeks, but the hard part is how do you make sure they don’t have repeated recurrences. That ends up being much more detrimental to the vision in the long term because the next time they have a recurrence, scarring can form, and that can be what really affects the patient.” Concerns for future surgery Dr. Hamrah said antiviral treatment shouldn’t get in the way of other procedures as long as the patient’s disease is under control. If they have a history of herpetic eye disease, they’re at risk of developing it after surgery, he added. Dr. Raju said that it is documented that the process after surgery can cause recurrences in herpetic keratitis. “I’ve seen it recur after cataract or cornea surgery, and it can lead to poor healing in corneal surgery,” she said. There are some who think patients with a previous history of herpetic keratitis shouldn’t have refractive surgery, but Dr. Raju thinks it’s possible, knowing how long it’s been and doing prophylaxis. But you should have a long conversation with the patient about this. For all surgeries, Dr. Raju recommends prophylaxis at least 5 days before and at least a week or longer after. If it’s cornea surgery, she might taper to prophylaxis doses at 1–2 weeks postop, but won’t take them off completely. There’s no hard rule on what amount of time is most appropriate. “For a full thickness graft, I might not take them off antiviral or topical steroids, but for cataract surgery, I think you can,” she said. “It also depends if the patient has a scar and you know they’ve had multiple episodes already.” Dr. Raju again stressed that different patients react differently, so the conversation and explanation to the patient will be very important, particularly why a treatment may be something that they need to do every day. “We’re doing it now so it doesn’t affect their vision later,” she said.
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