EyeWorld Asia-Pacific March 2020 Issue

EWAP MARCH 2020 29 SECONDARY FEATURE by Ellen Stodola EyeWorld Editorial Co-Director S ome patients take a variety of medications, and it’s important for ophthalmologists to know what medications patients are on and how they might affect the eye. Christina Weng, MD, Pravin Dugel, MD, and Robert Noecker, MD, highlight some of the medications that may affect the retina and optics nerve, what to look for, and how to handle these patients. Hydroxychloroquine One of most common of these medications is hydroxychloroquine, Dr. Weng said. This is primarily used to treat autoimmune diseases, like rheumatoid arthritis and lupus, but it can have a negative effect on the outer retina, particularly the photoreceptor ellipsoid zone, as well as the retina pigment epithelium (RPE). The RPE is a common theme where a lot of these toxicities occur, she said. Hydroxychloroquine retinal toxicity typically manifests in a slow, progressive manner, Dr. Weng said, adding that this drug probably has the most data on associated toxicity. We try to follow formal screening guidelines, though most patients don’t have toxicity during the initial period using this medication, she added. It’s thought that less than 1% of patients have toxicity at the 5-year timepoint, but if you look after 20 years, up to 20% will have some degree of toxicity, so that’s why screening is so important, Dr. Weng said. Hydroxychloroquine causes irreversible toxicity in the macula and retina, Dr. Noecker said, so the ophthalmologist’s job is to establish a baseline and monitor the patients moving forward. The incidence of toxicity is low, he said, but it does correspond to the dose that patients take and how many years they’ve been taking it. “There’s no magic cutoff,” he said. “But the longer they’re taking it and the higher dose, the higher the risk.” Dr. Noecker said it’s a good idea to watch these patients every 6 months or so, taking photos for comparison. He said to look for characteristic changes in the macula. Frequently, the earliest changes are the functional findings, like visual field or electrophysiology, but it can be subtle, he said. “We usually recommend before patients start that drug that the rheumatologist should send them to us for a baseline examination, and we’ll dilate the eyes and take a look to see if there’s any changes in the eye,” Dr. Weng said. At this point, she said it’s particularly important to look for macular degeneration. In addition to visual fields, spectral-domain OCT is very important as well. That’s where you’ll first see the atrophy of the ellipsoid zone, often before there are any visible findings on fundus examination and hopefully before the RPE is involved, she said. When it is involved, the prognosis gets more grim. OCT is wonderful for detecting this, according to Dr. Weng. She also recommends fundus autofluorescence or a multifocal ERG, if available, which can help draw out subtle abnormalities in patients with early disease. There have been reports that even after discontinuing the medication, you can continue to have progression for some time, Dr. Weng said. Thus, even after patients stop the medication, they need to keep following up. Patients may notice a central or paracentral scotoma, Dr. Weng added, and on OCT you’re looking for parafoveal outer retinal changes. Most patients don’t recognize anything in the earlier stages, she said, so you’ll probably see the changes on these tests before patients start complaining of symptoms. If a patient starts to exhibit signs of toxicity, Dr. Weng recommends working with the patient’s rheumatologist to seek an acceptable alternative medication to avoid further potential long-term effects. Dr. Dugel agreed that hydroxychloroquine is probably the most common drug you need to screen for. It turns up as Drugs your patients are taking and their impact on the retina, optic nerve AT A GLANCE • It’s important to pay attention to the medications your patients are taking—some are toxic to the retina or optic nerve and may have irreversible effects. • Hydroxychloroquine is a common medication but may not show toxic effects until after many years of use. It’s important to monitor these patients and to co-manage with the prescribing doctor. • Some of the toxic effects/signs of drugs like ethambutol and pentosan can mimic other retinal issues, so it’s important to keep a close eye on medications your patients are taking and to screen. This article originally appeared in the January-February 2020 issue of EyeWorld . It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp. Contact information Dugel: pdugel@gmail.com Noecker: noeckerrj@gmail.com Weng: Christina.Weng@bcm.edu A 56-year-old female with lupus had been taking hydroxychloroquine for more than 30 years without retinal surveillance. Spectral domain optical coherence tomography revealed bilateral parafoveal atrophy of the ellipsoid zone and outer retina. Note sparing of the central fovea, which allowed the patient to maintain 20/20 visual acuity.