Over 2,000 years ago, a Greek physician wrote that his patients experiencing intense headaches also fled the light. Experienced by 90% of people with migraine, photophobia is a distinguishing characteristic of this disease. What causes this light sensitivity? How does it define the migraine experience? What new therapies are available to address this often-ignored symptom?

Deborah I. Friedman, M.D., M.P.H., FAAN, is a professor in the departments of neurology and ophthalmology at the University of Texas Southwestern Medical Center. A neuro-ophthalmologist, she is chief of the division of headache medicine, and the founding director of UT Southwestern’s Headache and Facial Pain Program. She is board certified in neurology, with subspecialty certification in headache medicine. 


What causes light sensitivity in people with migraine?

Dr. Friedman: The retina of the eye has different cells that control our vision, called the rods and cones. The cones are responsible for color and our central vision, and the rods are responsible for seeing light and dark. These and some other small cells transmit back into the brain, to the thalamus, which is like a huge relay station. The thalamus then projects to other places in the brain, including the cortex, where we have awareness of pain and light sensitivity. All the fibers that receive information from those retinal cells are in very close proximity to the fibers that come up from the brainstem and those are part of the trigeminal vascular system that controls pain.

Should someone with photophobia try to avoid light?

Dr. Friedman: This is a very common question. However, it’s not a good thing when people start gradually decreasing the amount of light they’re exposed to because cells in the retina begin to “dark adapt.” Some people install blackout blinds, wear sunglasses indoors, or eat in the dark. While it’s true they’re very light sensitive, the fear of pain increases anxiety, which can also trigger migraine. We try to find the least amount of protection from the light where people can still function normally. Many try using FL-41 tinted glasses or lenses, which block the blue wavelength of light, while some actually do better blocking red wavelengths. While others use super dark glasses, they don’t block the wavelengths that are actually the problem. 
Are computer and phone screens a problem as well? 
Dr. Friedman: Screen time in general has created a lot of challenges for people with photophobia and migraine. While photophobia comes from migraine and from the brain, it can also be caused by other eye conditions. One of the most common causes of photophobia is dry eyes, and a lot of people with migraine have dry eyes, sometimes medication-related. When you’re reading or working on a screen, it’s normal not to blink as much. That means you’re not lubricating the cornea sufficiently, so it can dry out. And if the cornea dries out, it can cause blurred vision or pain. You might start straining, and then your neck gets sore. Between all that and the exposure to the luminance on the screen, it can make photophobia a lot worse. 
Watch the full interview for answers to:

• Is migraine the only headache disorder that has light sensitivity as a symptom?
• Is light sensitivity a premonitory symptom or is it a trigger of migraine?
• Is light sensitivity a chronic condition?
• Is light sensitivity something that can develop from another condition, such as concussion?
• What causes light sensitivity?
• Should people with light sensitivity completely avoid the light, or is it better to learn to adapt to it?
• What protections are there for people with light sensitivity?
• Should people with light sensitivity keep their home environments dark at all times?
• How can you tell the difference between photophobia as a trigger and as a premonitory symptom?
• Are tinted lenses helpful?
• When should someone with photophobia see a specialist?
• What kind of specialist should they see?
• Are the CGRP medications helpful to those with light sensitivity?
• Is our modern world of excessive screen time and “Zoom fatigue” causing more photophobia?
• How can someone tell that their photophobia might be chronic?

Watch Dr. Friedman’s interview preview here, or order it as part of the Migraine World Summit package from this page.