As the festive season arrives, homes, streets, and shops are decorated with Christmas lights and decorations. While many people enjoy bright, flashing designs, others prefer softer and more subdued lighting. Although intended to spread joy, certain types of festive lighting can cause discomfort or distress for some individuals.
Flashing lights are popular, especially during Christmas, since they attract the eye easily. Nevertheless, studies have always indicated that the use of flashing lights can trigger seizures among individuals with epilepsy. This is because quick flashes can synchronize neural activity in areas of the brain that are already hyperexcitable. Autistic individuals may also be particularly sensitive to flashing lights due to heightened sensory sensitivities. Similarly, people who experience migraines may be affected, as bright, flickering contrasts can overstimulate the visual cortex and provoke headaches.
Flashing lights can be unpleasant even for those without underlying conditions, especially when the flashing is rapid. Lights that flash more than three times per second are more likely to overload the visual cortex. As most of the modern decorations can be customized, the display can be made more comfortable by reducing the flashing speed or disabling flashing altogether to create a more comfortable display. Even lights that appear steady can cause discomfort.
Some lights create an invisible flicker that is too fast to be perceived by the eye, but can be easily spotted by capturing the lights with the slow-motion video mode of a phone. Invisible flicker has been attributed to headaches, impaired reading, and high visual fatigue. Flicker can be especially problematic for individuals with sensory processing differences, including heightened sensitivity to light, color contrast, sound, touch, or movement. Although researchers have not yet fully understood how flicker affects different populations, some individuals are far more sensitive to certain types of lighting than others.
White Christmas lights usually come in two types: cool white and warm white. Cool white resembles daylight and supports alertness and concentration, while warm white mimics sunrise or sunset and creates a more relaxing atmosphere. A large percentage of those with sensory sensitivities are those who have autism, and tend to prefer warm white lighting, as cool white can be uncomfortable to look at, particularly over extended periods.
Red and green are traditional Christmas colours, but red is often reported as the most uncomfortable. One possible reason is that photoreceptors responding to red light generate increased activity in the brain’s gamma frequency range, a fast brain rhythm. Discomfort is greater when red is very deep, when it flickers, or when it is paired with strong contrasting colours such as green or blue, making it feel more intrusive. Visual strain can be reduced by choosing red and green shades that are closer in tone and by avoiding alternating red and green lights.
Brightness is another important factor. Many individuals are sensitive to intense lighting, including those with sensory processing differences. Excessive brightness can cause fatigue, irritation, or feelings of being overwhelmed. For most people, any discomfort caused by Christmas lights is mild and short-lived. For others, however, it may result in headaches, nausea, fatigue, or sensory overload.
Sensitivity to light varies widely. Simply recognizing that people perceive decorative lighting differently can make a meaningful difference. Small adjustments, such as lowering light settings, can help maintain the warmth and joy of holiday decorations while making the festive season more comfortable and inclusive for everyone.
References: Manning C, Wilkins AJ. Bright, flickering, and flashing lights really can be bad for you – here’s how to have a visually comfortable Christmas. The Conversation. Published December 17, 2025. Accessed December 18, 2025. Bright, flickering and flashing lights really can be bad for you – here’s how to have a visually comfortable Christmas
