If you've ever tried a pair of Gunnar ambers you'd know what real blue light filtering is. With them on, it's not a subtle effect. You see with an amber tint. The monitor just appears less noisy. I've worked 12 hours straight in them in the past after which I'm physically and mentally tired but my eyes aren't. Without them I can't work, which is exactly how you know they're working.

If you're a programmer just looking at text all day, they are worth every penny. If you're a designer and color perception is important to you, you're out of luck.

Not affiliated to Gunnar in any way. Just a happy customer of 6 years.