Those of us who care for patients with migraine dread seeing patients who come to the office wearing dark sunglasses, even in a dimly lit examination room. In neuro-ophthalmology, the "sunglasses sign" is a predictor of non-organic visual loss and is often associated with a lawsuit, disability, workers' compensation claim, or a highly positive review of systems. While not specifically studied in a headache medicine practice, the sunglasses sign often goes hand in hand with chronic migraine, severe light intolerance to the point of social isolation, comorbid depression, and anxiety. It indicates that the provider is about to tackle a difficult case. Exposure to bright light may trigger a migraine, and heightened light sensitivity may herald a migraine attack. Photophobia is a major source of discomfort and disability for migraine patients during attacks and, in some cases, between attacks. It is often either overlooked or trivialized. The discovery of the melanopsin system clarifies that photophobia has a neurologic basis involving retinothalamic pathways and may be considered similarly to the central sensitization of migraine pain.
As Dr. Digre points out, dry eyes are a frequent cause of photophobia that is underdiagnosed, even by eye care providers. Patients with dry eyes often experience ocular itching, burning, foreign body sensation, a sense of dryness, reflex tearing, and conjunctival injection. Ocular inflammation, while uncommon, is another potential source of eye pain and photophobia. However, many migraine patients have photophobia that seems to be purely related to having migraine, and they sometimes take extreme measures to live in darkness. Patients with severe light aversion need our support and guidance to help them "come back into the light" gradually by treating any underlying ocular condition and slowly transitioning them to lighter lenses (including FL-41 and other tints). Awareness of the causes and treatments of photophobia, both ocular and central, is an important aspect of headache care that has the potential to vastly improve the quality of life of our patients.
—Deborah I. Friedman, MD, MPH
Professor of Neurology & Neurotherapeutics and Ophthalmology
University of Texas Southwestern Medical Center
Dallas
Suggested Reading
Bengtzen R, Woodward M, Lynn MJ, et al. The "sunglasses sign" predicts nonorganic visual loss in neuro-ophthalmologic practice. Neurology. 2008;70(3):218-221.
