Photosensitive Epilepsy: How Light Can Trigger Seizures

Photosensitive Epilepsy: How Light Can Trigger Seizures

Posted by Greg Bullock on 31st Jan 2017

Currently, the World Health Organization estimates that approximately 50 million people have epilepsy, a chronic condition that ranks as one of the most common neurological conditions. A small percentage of those nearly 50 million people—between 3 to 5 percent—have photosensitive epilepsy, which means light can trigger seizures and other symptoms of the condition. In this post, we explore the condition as well as how certain kinds of light can impact it.

What is Photosensitive Epilepsy?

Photosensitive epilepsy is a condition whereby symptoms can result from exposure to certain visual stimuli, predominantly related to light. The development of epilepsy can stem from a specific cause such as head or brain trauma as well as a stroke, but the majority—including photosensitivity—is believed to have a genetic link. Photosensitivity is more common with specific types of epilepsy, specifically juvenile myoclonic epilepsy, and may affect 40% of patients with this particular condition. It also seems to disproportionately affect more women than men; the onset of the condition also tends to occur during early adolescence. This may be further exacerbated by children and teens’ increased exposure to potential triggers such as cartoons, electronics, and video games. A person also need not be specifically diagnosed with photosensitivity in order to have a light-provoked seizure; researchers have suggested that any person with epilepsy may have as high as a 14% chance of experiencing a seizure brought on by light exposure.

photosensitive epilepsy brain activity
Recorded brain activity from a photosensitive epilepsy patient. Source: PubMed.

Types of Light That Triggers Seizures

For those with the condition, various types of light sources may stimulate the eye and brain in extreme ways. These triggers result in seizures due to irregularities within the brain or unbalanced neurotransmitters (chemical messengers). And it doesn’t take long either: exposure for as little as 4 minutes can cause a seizure! The Epilepsy Foundation cites the following common light-related triggers:

Speed or flicker (including fluorescent lighting)

Flickering or "high frequency" light sources are often triggering for those with photosensitive epilepsy. Frequencies of about 5-30 flashes per second are more likely to induce a light-triggered seizure. Common triggers might include television programs, cartoons, movies, video games, and concerts.

Fluorescent lighting poses its own special risk. Studies have shown that faulty fluorescent lights which produce a visible flicker can trigger epileptic brain activity. In addition, although researchers remain mixed, fluorescents as well as certain LED, television and computer screens can create an invisible flicker that is picked up the brain and could lead to seizures or elevated neurological activity. This may explain why many photosensitive epilepsy patients have cited fluorescent lights and other screen-related devices as prime triggers for seizures.

Intensity, brightness and contrast

Bright, sudden lights have a greater effect on the brain than softer, gentler ones. Strobe lights, camera flashes, and movie theaters thus carry the risk of a potential seizure. The light-to-dark ratio or contrast of a light source may also play a role in causing or triggering a seizure. This juxtaposition of intensely bright light followed by a sharp decrease in brightness (or vice versa) can cause the brain to become overstimulated.

Man with photosensitive seizures

Visual patterns

Although the intensity and speed of a light source are definite factors, we should also consider the pattern present within the lighting. Striped patterns—especially with high visual contrast and uniformity—have proven to be particularly dangerous for a photosensitive brain. Some researchers have even suggested that static images with these patterns can bring on a seizure, perhaps in as many of 30% of photosensitive epilepsy patients.

Color or wavelengths of light

Red or blue light have been identified as a possible culprit in provoking seizure activity in photosensitive patients. If a person also has migraine or other light-sensitive comorbidities, specific wavelengths of blue light can further aggravate these conditions—causing headaches, migraine attacks, seizures, or generalized light sensitivity as well. Read below to learn how TheraSpecs glasses for photosensitive epilepsy may be a solution to this concern.

Distance

Although certain light sources may not be triggering in isolation, they may become risky if viewed at a close distance. For some with photosensitivity, something as simple as sitting too close to the TV may cause a seizure. Devices with LED/LCD screens such as smartphones, tablets, and computers also pose an increased risk; viewing them too closely overstimulates the eyes and brain.

Photosensitive Epilepsy Treatment Tips

The most important step for photosensitive epilepsy treatment is to be properly diagnosed. This may require a consultation by a neurologist as well as undergoing commonplace tests for epileptic patients—such as an Electroencephalogram (EEG), which records electrical activity in the brain under certain conditions (including its responses to light). We recommend working with your doctor to help figure out an effective game plan to manage your light-induced seizures.

If you have already been diagnosed, there are many ways to manage triggers related to photosensitive epilepsy:

  • Installing an anti-glare cover for your computer monitor
  • Changing computer and display screen settings
  • Closing window blinds and covering up other contrasting light or visual patterns
  • Opting for natural or warm lighting to avoid fluorescents
  • Fixing any broken, flickering, or malfunctioning light (fluorescent or otherwise)
  • Taking frequent breaks to rest your eyes
  • Wearing polarized sunglasses for outdoor activities to reduce sharp glare
  • If confronted with a trigger, completely covering up one eye and avoiding direct exposure

Photosensitive epilepsy glasses

TheraSpecs photosensitive epilepsy glasses

In addition to the above recommendations, TheraSpecs fluorescent light sensitivity glasses with its indoor tint can block the wavelengths of blue-green light that could trigger photosensitive epilepsy as well as minimize the invisible flicker of artificial light sources that is a problem for so many. In fact, tinted lenses—especially with the rose color like TheraSpecs—have been supported by research linking the benefits of tinted lenses to photosensitive patients. In fact, 57% of those who used tinted glasses in one study found significant benefits in the form of reduced sensitivity and dizziness related to fluorescent lighting as well as fewer problems connected to screen time. Plus, non-prescription TheraSpecs styles are guaranteed by a 60 day return policy, so you can try them risk free!

References:

The Epilepsy Foundation, Shedding Light on Photosensitivity, One of Epilepsy's Most Complex Conditions

Panayiotopoulos CP. The Epilepsies: Seizures, Syndromes and Management. Oxfordshire (UK): Bladon Medical Publishing; 2005. Chapter 13, Reflex Seizures and Reflex Epilepsies.

Fisher RS, Harding G, Erba G, Barkley GL, Wilkins A; Epilepsy Foundation of America Working Group. Photic- and pattern-induced seizures: a review for the Epilepsy Foundation of America Working Group. Epilepsia. 2005 Sep;46(9):1426-41.

Hermes D, Kasteleijn-Nolst Trenite D.G.A, Winawer J. Gamma oscillations and photosensitive epilepsy. Current Biology. 2017; 27(9); doi: 10.1016/j.cub.2017.03.076.

Appleton R, Beirne M, Acomb B. Photosensitivity in juvenile myoclonic epilepsy. Seizure. 2000 Mar;9(2):108-11.

Harding, G., Wilkins, A. J., Erba, G., Barkley, G. L. and Fisher, R. S. (2005), Photic- and Pattern-induced Seizures: Expert Consensus of the Epilepsy Foundation of America Working Group. Epilepsia, 46: 1423–1425. doi:10.1111/j.1528-1167.2005.31305.x

The Epilepsy Foundation, Photosensitivity and Seizures

Myers C, Mefford H. Advancing epilepsy genetics in the genomic era. Genome Med 2015; 7(1): 91.

Quirk JA1, Fish DR, Smith SJ, Sander JW, Shorvon SD, Allen PJ. Treatment of photosensitive epilepsy using coloured glasses. Seizure. 1999 Dec;8(8):444-9.

Mayo Clinic, Epilepsy Diagnosis

Epilepsy Research UK, Epilepsy and Photosensitivity

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