Is Dark Mode Actually Better for Your Eyes? The Science

Walk into any startup engineering room. It looks like a cave. Everyone is using Dark Mode. It's a badge of honor. But is it actually good for you?

The Benefit: Blue Light Reduction

White screens emit massive amounts of blue light. At night, this mimics the sun, suppressing melatonin and wrecking your sleep.

Verdict: Dark Mode is unequivocally better for your circadian rhythm after 6 PM.

The Downside: The Astigmatism Halation

Roughly 50% of people have some form of astigmatism.

When you look at white text on a black background, your iris opens wider to let in more light (because the screen is dark). This wider pupil reduces depth of field and causes the white letters to "bleed" or look fuzzy. This is called the Halation Effect.

Verdict: If you have astigmatism, Dark Mode might actually cause MORE eye strain during the day.

The Compromise: Low Contrast Dark Theme

Pure Black (#000000) is bad. It creates too much contrast with white text.

The best dark modes used "Dark Grey" (like GitHub Dark or VS Code Default). This softens the contrast and reduces the halation effect.