En español | Have you ever awakened in the middle of the night, stumbled to the bathroom, hit the switch and … yikes!? Your initial response to that burst of light was probably to squeeze your lids shut or squint until your eyes adjust to your surroundings.
All of us have experienced light sensitivity at some time or other, but some people are extremely intolerant of light. It's known as photophobia, “when normal light causes discomfort or pain in people, to the point where they want to avoid it,” says Kathleen Digre, M.D., a professor of ophthalmology and neurology at the John A. Moran Eye Center, University of Utah, in Salt Lake City.
The source of discomfort might be a sunny day, a lighted computer screen, bright fluorescent lighting in a store, or oncoming headlights at night.
Some people may even become disabled, says Stephen Silberstein, a Philadelphia-based neurologist affiliated with Jefferson Health-Thomas Jefferson University Hospitals. “I have seen patients who literally cannot leave their house without dark sunglasses because of an increased sensitivity to light."
Actually, photophobia isn't a condition, but a symptom of other conditions. Though the list of culprits is a long one, it's most often related to neurological or vision problems.
Migraine is one the most common triggers. In fact, about 80 percent of people who have head bangers experience heightened sensitivity to light. “Two-thirds of patients say photophobia is their most bothersome symptom during an attack,” Silberstein says. “But there are many who also have an increased sensitivity to light between attacks."
Photophobia is also extremely common among those who have blepharospasm, involuntary eyelid muscle spasms originating in the motor nerves of the brain. In fact, one survey found that a whopping 94 percent of patients with blepharospasm experience some level of light sensitivity that impacts their daily lives. (What's more, light can actually trigger spasms.)
Other neurological conditions — including pituitary tumors, meningitis and traumatic brain injury — can cause light sensitivity, as can some medications, such as antihistamines, furosemide (used to treat high blood pressure or fluid retention and swelling due to conditions such as congestive heart failure), trifluridine (prescribed for viral eye infections) and certain antidepressants.
A cluster of eye conditions are linked to photophobia: chronic dry eye, cataracts, corneal abrasion, corneal neuropathy, optic neuritis (sometimes linked to multiple sclerosis), eye infections, uveitis (an inflammation of the eye), eye allergies and LASIK surgery.
People who have light-colored eyes can be more prone to sensitivity, says Lama A. Al-Aswad, an ophthalmologist affiliated with NYU Langone Health, “because the iris doesn't have as much pigment, which normally decreases the amount of light that goes into the eye.”
The first step in treating photophobia is figuring out what's causing the symptom; then you can tackle the underlying condition. “Intermittent photophobia associated with migraine, for example, usually responds to medications such as triptans, nonsteroidals [NSAIDS],” Silberstein says. “Or we might try something to keep the attacks from occurring in the first place, like a beta-blocker or topiramate.”
If you have dry eye, your doctor might prescribe medicated eyedrops or drugs that stimulate tear production.
Lifestyle changes also can make light sensitivity easier to manage. Sunglasses can block bright sunlight or glare bouncing off reflective surfaces (look for a polarized pair with UV protection). “The biggest mistake that people make is wearing really dark sunglasses indoors or putting dark shades on their windows,” Digre says. “That only makes things worse because you become dark-adapted.” Silberstein notes that one way to minimize sensitivity is to gradually transition from darkness to light, to give the eyes time to adjust.
And certain wavelengths of light can help alleviate or exacerbate sensitivity. “Sunlight has all of them, but it's the blue frequencies of light which seem to cause the most discomfort,” Silberstein says. A 2016 study, cited in the journal Brain, found that shades of green light seem to be the most soothing, particularly for those suffering from migraines. “I actually use it when examining patients with light sensitivity to make it more comfortable for them,” Digre says.
You can buy specially tinted lenses to block that bothersome blue light. Digre recommends FL-41 tinted lenses, which have a special “boysenberry-ish” tint to filter out blue wavelengths and decrease light sensitivity. The lenses can be obtained without a prescription, but, cautions Digre, not all so-called FL-41 lenses are the real deal. “Some of these lenses have not been tested properly,” she says. “We did a study where we took a bunch of lenses that claimed to block blue light. Some did and some didn't.”
Al-Aswad suggests going to an optic shop, trying on lenses, then choosing a trial pair to wear for a few days to see if it improves your symptoms. If you buy lenses, be sure the store will give you a guaranteed return if they don't work.
Migraine researchers from Harvard Medical School have come up with yet another way to combat photophobia: the Allay Lamp, designed specifically for those suffering from headaches triggered by light sensitivity. The narrow band of green light the Allay emits is believed to be kinder on the eyes than multicolored everyday light. It doesn't come cheap — the introductory price is $199. But for those searching for relief, the lofty price tag may be worth it.