ブルーライト

• Reading: ブルーライト
• Romaji: burū raito
• Kanji breakdown: From English 'blue light' → katakana adaptation ブルーライト
• Pronunciation: /bu.ɾuː.ɾa.i.to/

Meaning

Blue light emitted from digital screens, believed to disrupt sleep and cause eye strain.

ブルーライト became a major health buzzword in Japan as awareness grew about the potential effects of screen-emitted blue light on sleep quality and eye health. The term drove a huge market for ブルーライトカットメガネ (blue light blocking glasses) and screen filters. While scientific consensus on its dangers is mixed, the term remains deeply embedded in everyday health conversations and product marketing in Japan.

Examples

1. 寝る前のブルーライトが睡眠の質を下げるらしいよ。 Apparently blue light before bed lowers your sleep quality.
2. ブルーライトカットのメガネ買ったら目の疲れが減った気がする。 I bought blue light blocking glasses and I feel like my eyes are less tired.
3. スマホのブルーライト設定、ナイトモードにしてる？ Do you have the blue light setting on your phone turned to night mode?

Usage Guide

Context: health, daily conversation, product marketing

Tone: health-conscious, cautionary

Do Say

• 寝る1時間前からブルーライト避けるようにしてる。 (I try to avoid blue light starting an hour before bed.)
• ブルーライトカットのフィルム貼った？ (Did you put on a blue light filter?)

Don't Say

• 「ブルーライトで失明する」など過度に恐怖を煽る表現は避ける (Avoid fearmongering like 'blue light will make you go blind' — effects are debated and less severe than often claimed)

Common Mistakes

• Overstating the danger of blue light — while it can affect sleep, claims about severe eye damage are not well supported by current science

Origin & History

From English 'blue light.' Became a major health and lifestyle buzzword in Japan in the mid-2010s, driving a massive market for blue light filtering products.

Cultural Context

Era: Mid-2010s onward

Generation: All ages

Social background: Universal

Regional notes: Used across all of Japan. Japan is one of the largest markets for blue light blocking glasses, with major eyewear chains like JINS and Zoff promoting dedicated blue light cut lines.