Photosensitive epilepsy

Photosensitive epilepsy refers to the condition where seizures are induced by flashing lights or contrasting light and dark patterns. It is not a common occurrence, but it may be identified through an EEG test. Flashing or patterned stimuli can lead to disorientation, discomfort, or feelings of unwellness in individuals, both with or without epilepsy. However, it's important to note that experiencing such symptoms does not necessarily indicate the presence of photosensitive epilepsy.

How Prevalent is Photosensitive Epilepsy? Approximately 1 in 100 individuals has epilepsy, and among this population, around 5% are affected by photosensitive epilepsy. This type of epilepsy is triggered by specific frequencies of flashing lights or contrasting light and dark patterns. It tends to be more prevalent in children and young people (up to 5 times more common than in later stages of life) and is less frequently diagnosed after the age of 20.

Defining Photosensitive Epilepsy: Photosensitive epilepsy manifests as immediate seizures upon exposure to flashing lights or patterns. Diagnosis can involve an electroencephalogram (EEG) test, which may include specific assessments for photosensitive epilepsy. Typically, a flashing light at varying speeds is presented, though other triggering factors can be evaluated at specialized facilities. If any alterations in brain activity are observed, the stimulus is halted before a seizure ensues.

What Flashing Light Rate Can Trigger Seizures? Seizures can be triggered by flashing lights at rates between 3 to 30 Hertz (flashes per second), though individual sensitivity varies. Some individuals may be sensitive up to 60 Hertz, but sensitivity below 3 Hertz is uncommon.

Patterns that Can Elicit Seizures: Certain geometric patterns with contrasting light and dark elements, such as stripes or bars, can trigger seizures in some individuals. Patterns are more likely to provoke a reaction if they are dynamic, changing direction or flashing, as opposed to remaining static or moving slowly in a single direction.

Effects of Flashing, Flickering, or Patterned Stimuli: Flashing, flickering, or patterned stimuli can evoke feelings of disorientation, discomfort, or unwellness in individuals, regardless of whether they have epilepsy. However, it's essential to recognize that these reactions do not necessarily denote photosensitive epilepsy.

Treatment of Photosensitive Epilepsy: The primary method for addressing photosensitive epilepsy involves the use of anti-seizure medication (ASM). This approach aims to reduce the risk of experiencing seizures.

Possible Triggers for Photosensitive Epilepsy: Exposure to flashing or flickering lights or images with frequencies ranging from 3 to 60 Hertz (flashes per second).

Viewing contrasting light and dark geometric patterns, such as black and white stripes or checks.

Factors that Could Heighten Photosensitive Risk: Fatigue, stress, or excitement, such as prolonged video gaming without breaks.

An effect occupying the entire field of vision, such as being very close to a screen.

A quickly moving or direction-changing light and dark pattern causing a disorienting effect.

Viewing the effect against a dark backdrop, such as watching a screen in a dimly lit room.

Immediate Response to a Trigger: Covering one eye entirely with your hand can significantly diminish the impact of photosensitive stimuli.