Contrast & visual acuity

Optical glare

The scattering of light within the eye from bright light.

Optical glare can be caused by lights brighter than the dynamic range of luminosity vision during light and dark adaptation.

Screen glare is a form of optical glare caused by a device's brightness or reflections of light on the screen.

Bright light from the sun scatters in the eye, causing a glare and obstructing or limiting vision. Bright light from the sun scatters in the eye, causing a glare and obstructing or limiting vision.

How it affects UI design

Optical glare can affect contrast sensitivity and discrimination and causes legibility issues with text.

Supporting iOS increase contrast mode and Windows high contrast mode will help users who are experiencing optical glare.

In order to combat optical glare, users may need higher or lower contrast, as well as a lighter or darker colored interface. Consider personalization settings to give users the ability to adjust contrast and lightness to meet their needs.

Sources:

  1. Halos and Glare: Why Can't I See Well at Night?. WebMD. https://www.webmd.com/eye-health/halos-and-glare-causes-prevention-treatment
  2. Glare (vision). Wikipedia. https://en.wikipedia.org/wiki/Glare_(vision)
  3. Lens flare. Wikipedia. https://en.wikipedia.org/wiki/Lens_flare
  4. American Academy of Opthalmology. https://www.aao.org/image/glare-2