With both e-ink and LCD e-book readers in the news, the New York Times’s “Bits” blog has investigated which type of display causes more eyestrain (which I also addressed here). Not surprisingly, the answer is “it depends.”

Michael Bove, director of the Consumer Electronics Laboratory at the M.I.T. Media Lab, says different screens make sense for different purposes.

“It depends on the viewing circumstances, including the software and typography on the screen,” said Mr. Bove. “Right now E Ink is great in sunlight, but in certain situations, a piece of paper can be a better display than E Ink, and in dim light, an LCD display can be better than all of these technologies.”

The article also goes into detail about what causes eyestrain. According to Professor Alan Hedge, director of the Human Factors and Ergonomics Laboratory at Cornell University, it is caused by the movement of muscles in our eyes as we read. He recommends taking a break every 20 minutes.

The article also notes that LCDs are much better for reading than older types of backlit displays, because LCDs refresh faster than the human eye moves.

It is nice to see the article confirming what I have always known: either display technology can be good for reading as long as you use it in the right lighting conditions.


  1. The article also did not make clear that screens should be adjusted to the individual: Most LCD screens are preset to settings that make them look good in a well-lit store display, but not in your home; and everyone’s eyes are different.

    Setting brightness, contrast, type and background colors can make a huge difference between a painful viewing experience and an all-day-comfortable experience. But as most people don’t take much time to optimize their screen settings, and many never adjust them at all, so they become convinced that the screen itself “hurts their eyes.”

    The “Cleartype” setting that now comes standard on most Windows devices makes a huge difference in screen viewing quality… and most people don’t even know how to find the setting (go to Display Properties, select the Appearance tab, and click the Effects button to find the Cleartype setting, to smooth fonts on the screen).

    I use the Cleartype setting on my PC,laptop and PDA, and I can read on them all day long.

  2. I’d think BlurType (which is what I like to call it) is more conducive to eyestrain than anything else really – it blurs the edges of fonts, reduces edge contrast and in addition suffers from colored artifacting, particularly at lower point sizes. It’s possible to disable it in Windows thankfully, but it’s not very intuitive.

    The problem is there’s also a different type of anti-aliasing that has to be turned off in addition, and it’s even worse than CT – leading people incorrectly to believe that turning CT on is a good thing.

    The real solution to this is very simple: higher DPI screens. With a high DPI, there’s no need to resort to anti-aliasing hacks like CT, and it’s also a part of the reason why text on ebook readers looks as good as it does.

  3. Frode,
    Studies have shown that the muscles in and around the eye work less when viewing anti-aliased type, which reduces eyestrain. “Softer-edged” type looks more natural to the eye, as opposed to harder, bitmapped text that causes the eye to move around more to examine the jagged edges (a subconscious movement, but nonetheless causes eyestrain). That’s why Cleartype works so well and makes viewing easier.

    This applies even on high-DPI screens. Maybe the blurred edges, reduced edge contrast and color artifacting are more evident on low-DPI screens, but on a typically-available LCD screen (those used on standard PC monitors, laptops, PDAs, etc) are fine enough that they do not display those artifacts.


  4. That study you linked to isn’t actually readable – it’s just the abstract. I also seriously question the validity of a test that involves only 18 test subjects in a Microsoft controlled setting, and performing both subjective and objective tests.

    The issues I mentioned are clearly visible on a standard 24″ screen at 1920×1200 (94 dpi). I also see them on my laptop at 1280×800, 15″ screen (98 dpi). ClearType also uses sub-pixel rendering, which means that the effective dot pitch for edges should be much higher, but unfortunately the color fringing and resulting blur becomes too distracting. It basically feels like I need glasses, and my eyes are constantly working to bring the text into focus, giving me a headache – that’s eyestrain.

  5. Well, as others have pointed out, and not to sound rude, but… that’s you. Under those same specs, I have an easier time reading, and can read screens like that all day long (and do, on a daily basis). No eyestrain, beyond that of reading all day, which you will get on any screen, even an E Ink screen, without breaks.

    If you know of any studies that demonstrate that Cleartype does not improve reading and reduce eyestrain, you can always cite them here… in fact, I highly encourage it, since this particular subject is rife with personal anecdotes, but slack of hard evidence.

    But I think the lack of hard evidence is evidence itself that the subject is simply too subjective to allow absolute statements.

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