If you caught my previous post, “Peepers Pooped? Here’s Help For Tired Tech Eyes,” then you know I’ve got issues with headaches, tension, and eye strain. And in this battle with my tech displays, I think I may have found my best weapon yet. Recently, PCWorld covered an application called f.lux. Despite having been around for a few years, it’s still a relatively unknown program — a fact that surprises me, considering how widespread computer headaches and vision problems are.

F.lux is a free download that auto-adjusts display settings, based on your time of day and location, to deliver some pretty eye-soothing benefits. This isn’t simply a matter of brightness or contrast, but warmth (or color temperature, as measured in Kelvins):

“[F.lux] makes the color of your computer’s display adapt to the time of day, warm at night and like sunlight during the day… f.lux makes your computer screen look like the room you’re in, all the time. When the sun sets, it makes your computer look like your indoor lights. In the morning, it makes things look like sunlight again.”

There have even been studies done about how the glow from electronics can disturb the human body’s innate nocturnal timers (the site even lists a few), so the developer’s claim that f.lux could help you sleep better might not be far off the mark. Then again, it wouldn’t be the first time a developer has made big claims for wares that skimp on the real-life experience, so I decided to try it out myself.

The program offers settings that allow users to change the transition time (either 20 seconds or a gradual change over an hour), as well as type of lighting — tungsten, halogen, fluorescent, daylight or a custom option. (Uh, why is fluorescent in there? I guess everyone’s got their own preference, but yeesh.)

In a nutshell, this software made a very palpable difference on my display. (I’m using a MacBook Pro with Lion, but there are also downloads for XP, Vista, 7 and Linux, in addition to OS X.)

During the day, the tones on my external monitor work well in the daylight, but the real wow factor occurs in the evening — the bluer day hues visibly change as the sun sets, with the software imbuing my screen with warmer, mellower tones right before my eyes. And you know what? Maybe I’m imagining things, but this really does feel like it’s having an impact on my physical well-being. There’s no visual strain or “brain squeeze,” which I suffer pretty chronically, and those changes in color might be noticeably different, but after a few minutes, I get used to it and get on with my work without any distraction.

Everyone’s mileage varies, though. For me, the visual difference didn’t take long to get used to. Others might find it takes longer, or even decide that the change is too much for them. But for anyone trying this out, I’d recommend giving it a couple of days before making up their mind.

There is, however, one huge caveat: Photographers, graphic designers or anyone else who relies on color accuracy will obviously not be delighted about their monitors auto-adjusting. And while they can pause it for an hour, nothing less than quitting it completely will work for long-haul projects. Still, even with this irritation, this application is totally worth it, especially for anyone tied to a computer after the sun goes down. It’s simple (elegantly so) and user-friendly to tweak, automatically works, and is totally free.

So after testing it, I’ve become a big fan of this program. I probably said it best when I first loaded up f.lux: I was Skyping with a friend when I exclaimed, “Whoa…” Naturally, she asked me what was up, and I said, “If my eyeballs could speak, they’d be saying, ‘Ahhhhhhh…’ ”

Let me know if you give it a go. I’d love to know what you think.

[via PCWorld, source F.lux]

To better illustrate, here’s a video demo. It’s a bit long in the tooth, having been made in 2009, but it still offers a fairly decent idea of how it works.