Blue Light Filter on Phones and Computers: Protect Your Eyes at Night

All screens — phones, tablets, computers, and televisions — emit blue light as part of the visible light spectrum. During the day, blue light from the sun is natural and helps keep us alert. But in the evening, blue light from screens can interfere with your body's production of melatonin, the hormone that helps you feel sleepy. This can make it harder to fall asleep at night and can contribute to eye fatigue.

A blue light filter — sometimes called "Night mode," "Night Shift," or "Warm display" — shifts the colors on your screen toward warmer oranges and yellows in the evening. This reduces the amount of blue light reaching your eyes without making the screen harder to see. Many people find their eyes feel less tired and they fall asleep more quickly after using screens with blue light filters turned on.

Every major phone and operating system has a built-in blue light filter that is free and already on your device. On iPhone, it is called Night Shift. On Android, it is usually called Night Light or Comfort View. On Windows, it is called Night Light. On Mac, it is called Night Shift. All of these can be set to turn on automatically at sunset and turn off at sunrise. So you never have to remember to switch them.

The strength of the filter is usually adjustable — a slight warming is subtle and barely noticeable, while maximum warmth gives the screen a strong orange tint. For most people, a moderate setting provides eye relief without making colors look too unnatural.

Using a blue light filter is one of the easiest, lowest-effort things you can do to reduce evening eye strain and improve sleep quality.