Multifocal ERG, Humphrey Visual Field Testing, and Fundus Autofluorescence Contribute to Diagnosis
A woman in her mid-20s was seen for a new gray spot in the vision of her left eye in 2019. She had experienced an episode of optic neuritis of the left eye three years earlier, which resolved without treatment. She had refractive surgery in 2018.
She described four days of bright flashes in the vision, off to the left in the left eye, and a flickering, with variable intensity depending on ambient lighting.
She was able to see the photopsia with her eyes closed. For two days, she noticed a gray spot in the same area, which seemed to be enlarging. There was mild pain/soreness of the eye, slightly worse with movement. The rest of her vision was clear. She had no neurologic symptoms.
Running the Tests
On examination, her vision was 20/20 in both eyes. Color vision was normal. She had no relative afferent pupillary defect. Stereopsis was 9/9. Critical flicker fusion was normal in both eyes.
Humphrey visual field (HVF) testing showed an enlarged physiologic blind spot in the left eye. She noticed that during visual field testing, there was a blue hue around her scotoma.
Fundus examination showed a trace of optic nerve edema left eye (OS), rare vitreous cell, and a normal appearing retina (Figure 1).
Multifocal electroretinography (mfERG) showed depression of responses in the region of the enlarged physiologic blind spot indicated by blue area OS. The right eye was normal.
Fundus autofluorescence (FAF) showed marked hyperfluorescent spots in the area of the blind spot in the left eye. The right eye was normal (Figure 1).
Diagnosis: Multiple Evanescent White Dot Syndrome
She was diagnosed with multiple evanescent white dot syndrome (MEWDS), a rare unilateral, self-limited condition characterized by multiple yellow-white retinal lesions that primarily affects women aged 14 to 47.
Since there is no diagnostic laboratory test for MEWDS, electrophysiology and clinical imaging tests are essential for diagnosis.
Over the next few months, her symptoms resolved without treatment (Figure 2).
About the Authors
Dr. Warner is chief of neuro-ophthalmology and specializes in evaluating and treating complex visual complaints that can be due to optic nerve or brain disease.
Dr. Larochelle specializes in uveitis and ocular immunology, comprehensive ophthalmology, and cataract surgery.
Dr. Creel directs electrophysiology at the Moran Eye Center.
About Moran’s Electrophysiology Service
Moran’s electrophysiology eye testing service has been directed for 40 years by Donnell J. Creel, PhD, who is a leader in the field and actively involved in research to improve electrophysiological testing.
Electrophysiology technology is similar to an electrocardiogram (ECG) in that it shows the health of the retina, similar to how an ECG reflects the health of the heart muscles. It is key to diagnosing and following the progression of disorders affecting the retina.
Educational resources for clinicians are available at webvision.med.utah.edu, including Dr. Creel’s widely viewed internet chapters on visual evoked potential and electroretinogram (ERG) procedures. His video on multifocal ERG, the most recent advance in ERG technology, is available on the Neuro-Ophthalmology Virtual Education Library (NOVEL).