What I am about to ask is related to a similar question I asked. Several people suggested several solutions, but nothing worked for me. That particular LCD (ViewSonic) continues to cause immense eye strain to my eyes.

I recently purchased an HP x22LEDc LCD. I use it with my 15" MacBook Pro (those of you who have read the post I've linked to may have noted that in that post I mentioned having a 13" MacBook. Since then, I have moved to a 15" MacBook Pro). I use the mini-DisplayPort (thunderbolt) to DVI adapter to connect the MBP to the screen. I use it at the native resolution. The refresh rate is fixed to 60Hz, and I can't change it to anything else from within OS X. The panel on the LCD provides much more options to configure all sorts of things. However, I still feel the strain. It is definitely not so great as it was with the ViewSonic LCD, but it is there, and it leaves me eventually with headaches.

I feel nothing while working on the glossy 15" display of my MBP. I can work for hours without so much as a problem. However, after ten or twenty minutes working on the HP LCD, I can start to feel the strain, and later on, the headaches.

I have tried every conceivable setting. Tried a different number of brightness and contrast settings, tried different colour temperatures, tried calibrating the colour profile through the MBP display calibration utility, but, apart from decreasing or increasing the strain to some extent, I couldn't get rid of it. I also use the Apple Font Smoothing hack to set the font smoothing value to "2". (I've a blog post that explains the Apple Font Smoothing thing for those who may not be familiar with it).

So, well, here's what I want to ask: Why is this happening? I would really like to use the 22" LCD, especially my mechanical keyboard with it. But I can't. And what if anything can I do to possibly make a difference?

Any feedback on this will be greatly appreciated. Many thanks!

PS I should mention that I'm nearsighted, with a dioptre count of -6 both eyes. However, I should think that if there was something amiss with my eyesight that was causing the strain, it would show up while working on both my MacBook and MacBook Pro. If I am wrong, please do tell me.

  • Have you talked to your optometrist? More of an expert than anybody here. Nov 10, 2012 at 16:36

8 Answers 8


I can sometimes detect with my naked eye if a monitor is using 60 Hz refresh rate. Rumor has it that 60 Hz is the frequency that somehow resonates with internal frequencies of the body, whatever that means.

In the past, with a CRT monitor, that was a real pain for my eyes, so I had to drop resolution in favor of refresh rate. With LCD screens, that's normaly not a problem but you may be more sensitive to that. Try to get hold of a large monitor with high refresh rate (85 Hz or higher), even if only for ten minutes, and see if it helps.


Also, notice that with LCDs, it's strongly recommended NOT to set the resolution to anything other than the native resolution of the screen. Because, LCD's real pixel size is fixed and if you change the logical pixel size (which naturally changes with resolution), you get all sorts of mismatch and readjustment: two pixel wide lines can be displayed as two or one pixel wide depending on the position on screen, which really makes things fuzzy like soap.

I'm not sure whether modern OSes can compensate for that with sub-pixel positioning (that is, calculating the color of a real pixel based on colors of virtual pixels that correspond to it in your resolution of choice). It is known that Mac OS X discards font's alignment to real pixels in favor of sub-pixel rendering and I quite suspect that it makes prolonged reading harder. I also don't know if the Apple Font Smoothing hack you mention is related to the font sub-pixel/real-pixel rendering issue.


One theory that there is some problem with the backlit.
try different brightness settings, perhaps it gets better at some.

Here is why:
With the fluorescent backlit especially and with LED as well you get the backlit working at certain frequency as it is lit in PWM manner (this does not have anything to do with refresh rate you set at PC). The brightness of the backlit is set by the pulse width at certain frequency. The frequency might be low by design, or there might be something wrong with the PWM driver and you can have a secondary pulsing, which may go away at certain brightness settings.

One way to do check if the screen is pulsing is by turning your head so it is at the outer edge of your sight.

Another one is by taking picture in dark condition while turning the lens, so the screen travels through the frame... and counting ghosts on the resulting image.


I have no experience with Mac, only with Win XP/7 or various linux distros. I have also "bad eyes" and every new LCD I always have to decrease brightness by about 30% and also contrast a little bit. However, you say this did not help.

So there is a second question - are the used fonts etc. enough big for you? I always have to reconfigure the OS to have enough big fonts and icons. I do not know which resolution do you use for your laptop and for the monitor. For example, I have 24inch full HD display, but I use only 1600x900 resolution as the native one results in too much fonts and icons. OK, changing display DPI often helps but not all apps respect it.

I would recommend to try to set bigger fonts (I use bold Arial, smallest is 14 pt, but for browser I use 24pt) and bigger icons. Another problem could be the colors. Maybe the color scheme used in OS is to aggressive on the new LCD. For example I cannot stand the standard blue scheme in Windows XP - it really hits my eyes.

  • I use the LCD at its native resolution of 1920x1080. The fonts are small, but they seem fine. However, I have tried using bigger fonts, for example, on the terminal/console where I work most of the time. However, they have still caused me strain. And yes, I've tried turning down the brightness to 0, and even contrast quite low, but to no avail.
    – ayaz
    Jun 4, 2011 at 19:28

Try using the HP in a lower resolution. Depending on the viwing distance 1080p may be too much for your eyes to handle.

  • I have played with the viewing distance as well. I've kept it to an arm's length, half an arm's length, and somewhat closer. I know that when I use my MacBook Pro, if I keep it further away, I get a strain quickly because my eyes have to work more.
    – ayaz
    Jun 4, 2011 at 19:29
  • I'm going to try playing with a lower resolution, and get back to you with the result. Thanks.
    – ayaz
    Jun 4, 2011 at 19:44
  • Hi. I tried your suggestion. From the native 1920x1080, I dropped down to 1600x900 (which seemed better). But, there is very little to no effect. I could still feel the strain.
    – ayaz
    Jun 6, 2011 at 16:46

With regard to your eyesight, I find that when I use a notebook I tend to get closer to the screen (because I need to get closer to the keyboard) so I don't wear glasses, but when I use a PC or a notebook with an external monitor, the screen is that much further away so I use glasses specifically designed for protracted use of DSE. If I don't, I get headaches. Have a chat with your optician.

I'm myopic

  • In my case, I have to use glasses whether I am working on the LCD or the MacBook. Without glasses, I have to be really painfully close to the screen to be able to see properly.
    – ayaz
    Jun 4, 2011 at 19:42
  • I was advised to get a prescription specifically for use with computers. UK Health & Safety regs mean I can get them paid for by my employer, though they only need to contribute the minimum.
    – Tog
    Jun 4, 2011 at 19:56

Try 1280x800 - I use that on my 22" screen (native 1680x1050) and it helps alot.

Also use the scrollwheel on your mouse to always view websites in as big a size as will fit width-wise on the screen.

You could also try positioning the monitor in front of a window so that you can easily (and unconsciously) change focus - when thinking or being creative. Having a pleasant view of nature helps here!


I don't know much about mac, but I do know eye strain. I have an eye disease that requires me to get up and close to the screen. The best solution I have found is increasing the HZ as high as the monitor will handle, and having high contrast settings turned on. Larger fonts help, but they cause issues with some windows, and only get partially displayed. (my dream is to buy a 42" monitor) Hope this helps.

  • As side-note, the refresh rate of an lcd screen makes no difference, because the screen itself has a fixed refresh rate. What you mention is the refresh rate of the graphics card. On CRT screen it does make a difference. Dec 9, 2011 at 23:28

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