Light sensitivity (photophobia) and screens

What causes photophobia?

Photophobia isn’t a disease of its own. It’s a symptom that comes with many conditions, including:

• Migraine, where up to 80% of people have it during attacks¹
• Concussion and post-concussion syndrome²
• Blepharospasm and other neurological conditions⁵
• Dry eye and other problems with the eye’s surface¹
• Visual snow syndrome, where it’s one of the most common extra symptoms⁶
• Fibromyalgia, where everyday light and sound can feel unpleasant⁷
• ADHD and autism, where many people report sensory sensitivity^{3, 8}

Light sensitivity that comes on suddenly with eye pain, redness, vision changes or a severe headache needs prompt medical care.

Why can light hurt?

Light-sensing cells in the retina send signals to neurons in the thalamus that also carry pain from the trigeminal nerve system, the nerves of the head and face.⁴ When those pathways are sensitized, ordinary light registers as discomfort or pain.

Why are screens especially hard?

You can dim a room or wear a hat outside, but a screen is a light you look straight into for hours. Most are lit by white LEDs with a strong blue peak, and many add flicker: PWM dimming that pulses the backlight, and FRC dithering that flickers pixels.

Brightness, flicker and color

Turning the brightness down usually helps, but on a screen that dims with PWM, lower brightness means more flicker. DC dimming avoids that tradeoff. Studies disagree about which colors of light are worst; for many people, intensity matters most.⁵

Tips for screen use with light sensitivity

• Keep the room and the screen at similar brightness; a bright screen in a dark room is harsh.
• Turn the screen down, and try dark mode if it helps you.
• Cut glare from windows and overhead lights.
• Take regular breaks.
• Use a screen that dims without flicker and has no bare, glaring light source.