Treating the ‘zebra’ patient

Treating the ‘zebra’ patient

When Deborah Moy, O.D., started seeing blue flashing lights and experiencing significant visual field loss, and no one could figure out what was causing it, she realized that she was a "zebra"—the medical community's term for a patient with a mysterious condition.

"Not knowing whether you are going to lose your vision is stressful and frightening."

Dr. Moy, who at the time had her own practice in Albuquerque, New Mexico, started experiencing these symptoms suddenly in 2014.

"My Amsler grid on both eyes was extremely distorted," Dr. Moy says. "The vision part of it wasn't refractive, and my prescription hadn't changed, but the flashes of light were extreme. They were colored lights dancing around in the shape of a C. I explained that to many ophthalmologists, and they looked at me like I was crazy."

Over the course of seeing virtually every eye care expert in her area, she had blood tests, an MRI, CT scans, a fluorescein angiography, a visual field test, an electroretinography and fundus autofluorescence imaging. Yet, after all these tests, no one could tell her what was wrong.

Eventually, she went to a retinal dystrophy specialist, John Heckenlively, M.D., at the University of Michigan Kellogg Eye Center, and he diagnosed her with Acute Zonal Occult Outer Retinopathy (AZOOR). A rare autoimmune retinopathy, AZOOR causes permanent visual field loss in the periphery, mainly all of the rods, but typically spares central vision. Dr. Moy is now a patient in Dr. Heckenlively's clinical study.

However, with this diagnosis and her progression of symptoms—she is now legally blind—Dr. Moy had to end her 30-year career and sell her practice.

Diagnosing a rare ocular disease might not be in the purview of a majority of doctors of optometry. However, how a doctor handles and refers patients with mysterious symptoms is critical to the patient's eventual diagnosis, treatment and quality of life.

"For the 'zebra' patient, not knowing whether you are going to lose your vision is stressful and frightening," Dr. Moy says.

Dealing with a rare disease
As with any patient, doctors dealing with patients with potentially rare eye diseases need to take a good case history and listen to their symptoms before the examination, says Jay Haynie, O.D., a retinal disease specialist in Olympia, Washington.

"When I look at patients who have symptoms, and I'm not entirely convinced I know what's causing their symptoms, I always ask myself the question: 'What is the worst thing that could happen if we do nothing?'" Dr. Haynie says. "If you don't know what is causing the patient's symptoms, and you can't answer that chief complaint, I think you are obligated to reach out to colleagues who have more experience in the retina or ocular pathology who can explain those symptoms."

Dr. Haynie doesn't advise doctors to educate themselves on every rare retinal disease. The better approach, he says, is to be able to recognize when something isn't right. "I advise going back to the patient with unexplained symptoms and making the referral to a specialist who deals with pathology," he says.

Both Dr. Haynie and Dr. Moy recommend referring these types of patients to a university setting, which will have a host of providers. "Every state has a university with an updated ERG [electroretinogram], which will determine if that person has a cone or rod dystrophy," Dr. Moy says. She also suggests that optometrists keep an updated list of ophthalmologists who specialize in rare disease, regardless of where they are in the country.

Educating patients about low-vision resources
Dr. Moy recommends that all doctors of optometry attend a low-vision continuing education course to understand the full scope of the tools and resources available for patients today.

Dr. Haynie gives all his patients low-vision resources when they start experiencing loss of function that cannot be corrected with standard refraction, bifocals, etc.

"I encourage patients who are in the 20/40 to 20/70 range to start looking into low-vision resources," he says. That way patients can learn how to use the resource when they still have functional vision. Then, as functional vision starts to erode, patients will already be trained on the devices that will help them. "I think a mistake eye care providers make is waiting until it's too late, until the patient has 20/200, 20/400 central acuity, and they become very hard to rehabilitate," Dr. Haynie says.

Dr. Moy also recommends doctors of optometry be honest with patients about their limitations, and most of all listen to the patient, answer any questions and be honest about what they don't know.

"An optometrist or ophthalmologist shouldn't be afraid to say, 'I don't know what you have. I know it's something rare. Let me ask some of my colleagues who have more experience. Or let me order these tests,'" Dr. Moy says.

July 14, 2016

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