A Mexican study has found a smartphone’s night mode may protect users’ eyes from short-wavelength (blue) light more than blue light-reducing lenses.

Exposure during the evening to short-wavelength light from a smartphone screen has been found to have a detrimental effect on human health as it alters our circadian rhythms. To find the most efficient protection from blue light a team of researchers, led by Dr Emiliano Teran from the Autonomous University of Sinaloa, Mexico, compared melatonin suppression after using night-mode functions on digital devices and four different, blue-light filtering spectacles.

The night-mode functions in smartphones reduced melatonin suppression by up to 93%, with the warmest mode producing the least suppression, while blue-light-reducing spectacles reduced melatonin suppression by up to 33%, with coated lenses more efficient than tinted lenses.

A combination of both spectacles and night-mode functions could further reduce exposure to blue light and may be the optimal approach, concluded researchers.