我泪流满面啊。
Is E-Ink Really Better for My Eyes than My iPad?
Whitson Gordon
Dear Lifehacker,
I've heard that tablets with bright screens—like the iPad—can cause
eyestrain and other problems. Am I better off getting an E-Ink device like
the Kindle or the Nook?
Sincerely,
Troubled by Tablets
Dear Troubled,
The common belief goes like this: because tablet screens are backlit and
emit blue light, they cause greater eye fatigue than E-Ink, which isn't
backlit and is designed to look like a piece of paper rather than a screen.
Anecdotally, I've always believed this to be true; in fact, the headaches I
get most evenings (and their absence when I wear Gunnar glasses) would seem
to back that up. However, all the research I could find on E-Ink claims that
they don't offer any eyestrain benefits over LCDs. The New York Times
explains:
Today's screens are definitely less tiring to look at than older
displays, which refreshed the image much less frequently, causing a flicker.
Carl Taussig, director of Hewlett-Packard‘s Information Surfaces Lab, said
the 120 Hz refresh rate typical of modern screens is much quicker than our
eyes can even see.
"The new LCDs don't affect your eyes," Mr. Taussig said. "Today's
screens update every eight milliseconds, whereas the human eye is moving at
a speed between 10 and 30 milliseconds."
If that's true, then it's certainly possible that my glasses are just a
placebo, or that perhaps they solve problems not related to LCD screens
directly, but to reading—and that they'd help just as much if I spent all
day blogging on an E-Ink screen without breaks. Regardless, the research
says "no"—E-Ink isn't inherently better for your eyes.
However, each type of screen does have its own advantages and disadvantages.
Some examples:
Tablets like the iPad are much harder to read in bright light, and their
screens can produce a lot of glare. E-Ink screens, on the other hand, work
fantastically in bright light.
E-Ink has a low contrast ratio that is difficult to read in low light.
Tablets, being backlit, are much easier to read in darker situations.
Tablets may be great in low light, but if you're reading them in the
dark—particularly at night—the blue light can cause insomnia and other
problems. In that case, a paper book might be best—it's easier to read than
E-Ink in low light, and doesn't come with the problems of a tablet.
In the end, everyone is different, and you need to pick the type of screen
that fits your needs. If you're looking for an ereader to accompany you to
the beach, you'll definitely want to go E-Ink. If you're looking to read
inside and during the daytime, an iPad or Kindle Fire may be better. And, no
matter what you're reading on, take a break every 20 minutes or so if your
eyes are feeling tired. That's going to be a much bigger cause of eyestrain
than the type of screen you're using.
Sincerely,
Lifehacker
