Eyeworld

I WHAT YOUR PATIENT IS TAKING AND ITS EFFECT ON THE EYE N FOCUS 62 | EYEWORLD | JANUARY/FEBRUARY 2020 mistaken for a retinal problem, Dr. Dugel said, but it really damages the optic nerve. It's usually bilateral and symmetric and can cause photophobia, poor dark adaptation, and color changes. For patients on this drug, Dr. Dugel suggested regular assessment. Changes may be noticed in vision, visual field, and color vision, and it may also be helpful to look at the OCT. This can lead to a pretty severe optic neu- ropathy, Dr. Weng said. While there are no for- mal screening guidelines, patients will generally have toxicity appear 4–12 months after starting the medication. As such, many physicians bring patients in monthly during the first year. There have been reports of toxic effects being reversible, if detected early enough, Dr. Weng said, so time is of the essence in these cases. She added that this drug isn't often used long term. Pentosan Pentosan is another potentially toxic drug, used to treat bladder issues such as interstitial cystitis. It was only recently learned that pentosan can cause pigmentary maculopathy, Dr. Weng said, which can cause damage to the outer retina and RPE. This was found incidentally by an ophthal- mologist, Nieraj Jain, MD, who noticed that there was something that looked similar to macular degeneration and identified this drug as the common thread. This is a maculopathy that is located in the central macula, which is unfor- tunate, Dr. Weng said, because that's the area most responsible for central and sharp vision. This toxicity can closely mimic macular degeneration or geographic atrophy, she said, so many of these patients potentially had a pre- vious diagnosis of macular degeneration when it could have actually represented pentosan pigmentary maculopathy. No current screening guidelines exist, Dr. Weng said, and the full extent of damage or abnormality it can cause is unknown. She added that it's important to work with urology colleagues as physicians learn more about this condition. Dr. Dugel said that changes may look like dry macular degeneration and patients may be misdiagnosed. Patients with this type of "We know now with the OCT that there are subtle changes to look for early on in the ellipsoid zone to allow us to identify before seeing the bullseye pattern," he said. "What we'll see is the ellipsoid loss that has a kind of parafoveal distribution." The classic appearance may change a bit because toxicity may be more parafoveal in Caucasians but more peripheral in Asians. The point is that it's important to screen patients on a regular basis with OCT and catch potential toxicity earlier, Dr. Dugel said. Ethambutol Another drug with the potential for ocular toxicity is ethambutol, which is used for tuber- culosis treatment. It causes what is sometimes continued from page 61 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. Source: Christina Weng, MD

• Blank Page
• Blank Page (1)