I have 2 models of ipads - iPad 2 and iPad mini which I can use without eye strain. These are my main device to watch youtube videos and movies on-the-go for long periods of time. Both my iPad 2 and iPad Mini was on IOS7. I wanted to install an app, but it requires a minimum IOS8. So I decided to upgrade the OS of my iPad 2 to IOS 8, and immediately I got eye strain. So for me:
IOS7 = no eye strain (on ipad 2 and ipad mini)
IOS8 = eye strain
I tried someone's ipad 2 with IOS9, also give me eye strain. What is worse, is that once upgraded the OS, there is no way to downgrade to IOS7 again. Hours spent on the internet on how to downgrade, basically it can't be done. Apple has stopped signing older IOS versions to force people to upgrade to the latest IOS.
So now I have essentially "lost" my ipad 2, I cant use it anymore. Since I now know that newer version of IOS causes eye strain to me, I thought I would use this opportunity to buy a newer ipad model, but one that came with IOS7 (i.e. that has not been upgraded to IOS9 or 10).
I found that Ipad Air and Ipad Mini 2 was originally shipped with IOS7. All newer models are shipped with IOS8 or IOS9 from factory, so there is no way to get IOS7 on newer models. So I searched a long time for a new (old stock) Ipad Air that was manufactured in 2013 (before IOS8 was released) so that I know it is shipped with IOS7 right out of the box. Finally I found one seller who still has a new, factory sealed iPad Air, manufactured in 2013. I checked the serial number from the back of the box on a website, and it confirms that the ipad was manufactured in 2013.
So I opened the new iPad Air, set it up, lo and behold, it is indeed IOS7 inside. I was happy. But then after using it a 10 minutes, I get eye strain. I stopped using it for a few hours. Use the ipad again, and still get eye strain. I tried using the ipad Air for a few days, and it still give me eye strain. Damn.
So know I know, not only newer version of IOS (IOS8) give me eye strain, but the newer iPad hardware/retina display, at least the iPad Air, even when used with IOS7, also gave me eye strain. Which is weird because the ipad does not seem to have PWM. So there must be something else in Ipad Air's hardware/retina display is causing eye strain to me. This sucks. Not only the newer IOS gave me eye strain, but their hardware as well. Looks like I am stuck with my 4-year old iPad mini (still on IOS7), which thankfully can still work without giving me eye strain.
I have not tried every model and every IOS version of iPads. I am hoping that if there are some model and IOS version of ipad that you can use without eye strain, maybe it can work for me and for others here as well.
So what iPad model and IOS version can you use without eye strain?