Help a programmer take care of her eyes, please.

If you are squinting, something is the matter. You shouldn't have to consciously do anything to be able to focus on things- your eyes should be accommodating for you on their own. Why do you squint? Is the text blurry? Too bright? As for personal recommendations, I find that dim environments are awful on my eyes. Dim room + computer screen is annoying. Triply so if it is light text on a dark background. I get stripes in my vision from that. I also find that shadowy light is annoying. Lots of diffuse light (no shadows) works best for me. Lastly, it is harder to focus in dim light. Your eyes are like cameras, and cameras take crappy pictures in dim light.

I've worked as a developer for about a decade and I'd also recommend switching to white text on black backgrounds, as well as periodically looking at something in the distance. I tend to space out a lot at work so the latter is not much of a problem for me, but if you need to be reminded there are countless countdown timers for whatever platform you happen to be working on.

nthing setting your monitor color temperature to something yellowish. The biggest improvement for me came from http://www.codinghorror.com/blog/2011/11/bias-lighting.html: basically, put a lamp behind your monitor to reduce the contrast between your monitor brightness and the brightness around it.

Your ambient light should be about half the brightness of your display. http://www.pcworld.com/article/258703/how_to_eliminate_eyestrain_from_your_big_beautiful_pc.html. You should speak to your office managers to figure out a solution--if you have your own office, just turn off the overhead lighting and use a floor lamp. If you are in a cubicle farm you may have to do more wrangling to get ergonomically appropriate lighting.

Get the largest IPS monitor you can afford. You also may want to try a CCFL backlit monitor if you are using a LED backlit one now.

I have similar problems with my eyes, related to eyestrain and staring at a screen for 8 hours a day. My optometrist put a stronger prism in my glasses (I'm farsighted, and my eyes REALLY don't like to converge for things up close). A prism was the magic bullet for me - no more eyestrain, no more headaches. Sounds strange but keeping well hydrated helps me with headaches too. I keep 1/2 a lemon in my water bottle and suck it down like crazy all day to keep hydrated. My office is super dry. Nthing the suggestions for changing text size and icon size on the computer as well.

I have 20/20 vision (better than that, actually) but it turns out that what I really am is slightly farsighted, with a very powerful focusing mechanism. This allows me to pull focus close to my face, but after a while, that gets tiring. I had horrible horrible eye problems when I first got my laptop, because I am short and so the screen was right at the edge of the place where I had to really pull focus instead of just focusing. +0.75 glasses changed my life. I know you've tried +1.25, but if your vision is like mine -- you can MAKE it be 20/20, but you're naturally farsighted -- you may need stronger glasses.

Drink more water and remind yourself to blink more. Install http://www.workrave.org/, and follow all the exercises (not all of them are eye exercises). Take fish oil or flaxseed oil to help with dry eyes, if it doesn't interfere with your medication. Nthing f.lux, bigger font sizes, changing screen resolution and using a dark theme.

Also, try to blink more. Most people who stare at a screen decrease their blink rate, which means that eyes get dried out and painful pretty quickly. Gentle eyedrops could help too.