system
Given the following post, respond as if you're commenting on Reddit:
human
Is viewing a computer screen for most of the day harmful to vision?

Everything I've heard on the subject is just anecdotal/speculative, so I was wondering if there have been any long term studies on the effects of looking at a computer screen for a large portion of the day.  Or if there is a scientific basis for the idea that staring at a computer screen, or any object a fixed distance from your face, for the majority of the day can weaken your vision in any way?

I've heard advice that we should look out the window and into the distance every so often when using a computer for long periods of time, but is there any proven benefit to this?

Also, a friend mentioned that there are tribal populations with superior long-distance vision to us first worlders.  Is this true?  Would it be due to us not utilizing our long-distance vision as much as them, or more selection pressure on the tribal populations to have better vision, or both?
gpt
Optometric technician here.  There aren't really any conclusive studies that find it detrimental to stare at a computer screen all day.  There are 2 things that happen to your eyes: they get dry and they get tired.

When you're focused in on the computer screen, you go from blinking somewhere around 20 times a minute to about 8 times a minute.  That's why after awhile you blink and it burns a little; or you close your eyes and they burn for a sec or water up a bit.  Most of that is dryness, and it's kinda unavoidable.  You can either A: blink more or B: use some lubricating drops every so often to help your eyes feel better.

Looking at anything farther than 10 feet away makes your eyes converge, and they actively focus on anything up close.  Of course, this includes computer screens.  Towards the end of the day, if you're spending long hours on the computer, you may notice your vision get increasingly difficult to manage, or hard to focus.  This is where the looking away from the computer screen comes in.  When you stare at something in the distance every little while in the middle of the workday, you're letting your eyes relax, so they don't become locked in, so to speak.  A lot of optometrists will even recommend a set of glasses to wear solely at the computer, to reduce this strain, like Gunnars.

It's not uncommon for children to be hyperopic, or far-sighted.  Most children tend to grow out of it.  Vision problems are highly hereditary as well, so if you've got bad eyes, blame the 'rents.