Facebook Messenger has introduced a Dark Mode to help prevent screen glare, though the new feature is not yet available for everyone.
An incomplete version of the feature was rolled out in some countries, according to several reports from users on social media.
"Facebook Messenger, seemingly due to prolonged external nagging, has started public testing Dark Mode in certain countries," web app developer Jane Wong wrote on Twitter.
"They have put up a fair warning that Dark Mode isn't everywhere yet so don't complain when some UI burns your eyes off."
The dark mode works by changing the colour settings to reduce the brightness, which makes browsing through messages both easier on a user's eyes and their device's battery.
Previous studies have discovered that blue light emitted from the screens of laptops and smartphones can contribute to blindness.
In August, research by scientists from the University of Toledo, Ohio, revealed that prolonged exposure to the short-wavelength light triggers the generation of toxic molecules in the eye's light-sensitive cells.
This process can lead to macular degeneration, a condition that results in blurred or no vision in the centre of the vision field.
While it is thought that dark modes can help reduce eye strain, no studies have provided conclusive proof of whether the feature helps prevent this type of blindness.
Facebook Messenger follows several other popular apps to introduce the feature, including YouTube, Google Maps and Firefox.
WhatsApp, which is also owned by Facebook, is expected to introduce a similar feature later this year.
As well as avoiding shining bright screens into people's eyes, dark modes can also improve battery life. Phones that use OLED displays do not need to light up parts of the screen that are black, potentially reducing the energy needed while the app is open.
