Éblouissement

Éblouissement is the French term for the sensation of glare or dazzlement produced by bright light. In practice, it covers both the subjective feeling of discomfort caused by excess illumination and, in vision science, the objective effect of glare that reduces visual performance. The noun derives from the French verb éblouir, meaning to dazzle or blind.

There are two commonly distinguished forms: discomfort glare, which is unpleasant but does not necessarily impair vision, and disability glare, which reduces acuity or contrast and can lead to temporary blindness. Both arise when light sources are bright relative to the surroundings, or when specular reflections create intense light within the visual field. Factors include luminance of sources, duration, adaptation level, pupil size, age, and spatial distribution of light.

Common contexts include daylight conditions with strong reflections from snow, water, glass, or shiny surfaces, night driving with vehicle headlights, and indoor lighting with glare from screens or chrome finishes. In photography and cinematography, éblouissement refers to unwanted highlights or flash that obscure detail.

Mitigation involves controlling luminance and contrast: use diffused or indirect lighting, anti-glare coatings, shading, or screening, and ensuring appropriate contrast and uniformity of illumination. For eyewear, sunglasses or lenses with anti-reflective coatings reduce perceived glare; automotive and architectural design often employ glare-reducing geometry, coatings, and lighting layouts. Measurements such as the Unified Glare Rating (UGR) and veiling luminance quantify glare for safety and comfort.

In culture, the term can also describe a figurative overload of beauty or splendor, beyond its technical meaning.