半夜睡不著的時候，很多人都會拿起手機，刷微博或者看朋友圈。屋子里整體是一個黑暗的環境，如果看手機的時候側躺著，主要用一只眼睛看手機，那么等你翻身平躺，把兩只眼睛都睜開的時候，你會感覺到剛才看手機的那只眼睛什么都看不見。

Smartphone blindness happens when people lie on their side at night, with one eye against the pillow and the other staring at the smartphone screen. While one eye adjusts to the dark, the other eye gets used to the bright light of the high-resolution screen. But when they roll over and open both their eyes, the eye which has been staring at the screen cannot cope with the darkness of the room. Subsequently, with both eyes uncovered in the dark, the light-adapted eye is perceived to be “blind”.
人們晚上側躺著看手機，一只眼靠著枕頭，另一只眼盯著手機屏幕的時候會出現“智能手機眼盲癥”。一只眼（靠著枕頭的那只）適應了黑暗的環境，而另一只眼（看手機的那只）則適應了高分辨率屏幕發出的亮光。當你翻身把兩只眼睛都完全睜開的時候，之前盯著手機屏幕的那只眼睛無法適應房間內黑暗的環境。結果，兩只眼同時在黑暗環境中的時候，適應了光亮的那只就會出現“眼盲”的情況。

It usually takes several moments for the eyes to adjust, leading people to believe they are suffering from a severe problem.
通常，這種情況需要一段時間讓眼睛來慢慢適應，有些人就會以為自己得了什么重病。

A similar condition known as digital eye strain may also appear after long hours of staring at computer screen or smartphone screen. The sympotoms may include eye dryness, blurry vision and persistent headache.
另外一種相似的癥狀叫“數碼眼疲勞”，多半出現在長時間盯著電腦或手機屏幕之后，主要的癥狀有，眼干、視野模糊，以及長時間頭疼。

緩解眼疲勞小貼士：

1. Blink more often.
多眨眼。

Blinking is very important when working at a computer; blinking moistens your eyes to prevent dryness and irritation.
看電腦的時候眨眼很重要，眨眼能夠滋潤眼睛，防止眼干和不適。

2. Adjust your computer display settings.
調整電腦顯示設置。

Brightness. Adjust the brightness of the display so it's approximately the same as the brightness of your surrounding workstation.
亮度。將電腦顯示的亮度調整到接近周圍環境亮度的水平。

Text size and contrast. Adjust the text size and contrast for comfort, especially when reading or composing long documents.
字體大小和對比度。將字體大小和對比度調整到讓眼睛舒適的水平，尤其在需要長時間閱讀或處理文件的時候。

3. Take frequent breaks.
多休息。

To reduce your risk for computer vision syndrome and neck, back and shoulder pain, take frequent breaks during your computer work day.
為了緩解電腦視力癥狀以及頸、背、肩痛，在電腦前工作時要多停下來休息。

（中國日報網英語點津 Helen）