Eyeworld

I JANUARY/FEBRUARY 2020 | EYEWORLD | 61 by Ellen Stodola Editorial Co-Director are the functional findings, like visual field or electrophysiology, but it can be subtle, he said. "We usually recommend before patients start the drug that the rheumatologist 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 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 dis- continuing the medication, patients can contin- ue to have progression for some time, Dr. Weng said. Thus, even after patients stop the medica- tion, 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, so physicians will most likely see the changes on these tests before patients start complaining of symptoms. If a patient starts to exhibit signs of tox- icity, 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 the most common drug ophthalmologists need to screen for. It turns up as a classic bull- seye pattern of RPE loss, Dr. Dugel said, but by the time you see it, it's quite late and there's some evidence that it stays behind in the RPE cells even after stopping the medication. S ome patients take a variety of medica- tions, and it's important for ophthal- mologists to know what medications patients are on and how they might affect the eye. Christina Weng, MD, Pravin Dugel, MD, and Robert No- ecker, MD, highlighted some of the medications that may affect the retina and optic nerve, what to look for, and how to handle these patients. Hydroxychloroquine One of the most common of these medications is hydroxychloroquine, Dr. Weng said. This is primarily used to treat autoimmune diseas- es, 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 place where a lot of these toxicities occur, she said. Hydroxychloroquine-induced retinal tox- icity typically manifests in a slow, progressive manner, Dr. Weng said, adding that this drug probably has the most data on associated toxic- ity. "We try to follow formal screening guide- lines, 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 5 years, but if you look after 20 years, up to 20% will have some degree of toxicity, which is why screening is so import- ant. 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 for- ward. 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 the 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 Drugs 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 irrevers- ible 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 co-manage with the prescribing doctor. • Some of the toxic effects and signs of drugs like ethambutol and pentosan can mimic other retinal issues, so it's important to keep a close eye on medications that patients are taking. continued on page 62

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