The "nightshift" modes on digital devices are great, I think they should be turned on by default on most devices, especially because most non-technical people don't even think about these things and mostly don't touch these settings. The eye strain is reduced quite a bit, I can see by the quality of sleep I get if I have it turned on or off in the evening.

Having said that, it shouldn't be viewed as a substitute for the glasses. While the blue light is reduced a bit by the digital filter, the glasses actually reduce more than 90% of the blue light that hits your eyes, which is totally awesome. While I don't wear them every day at work, the difference between how tired m eyes get during the day is noticeable in the afternoon when I can relax a bit and don't have to concentrate on the designs and stuff that much.

Also, because we're staring intensely into a light source most of the time during the work hours, we don't blink as much as we should so the eyes don't get the moisture they need. I'd suggest buying eye drops and try to catch yourself when you've stared into the screen for some time and use them. These don't even have to be expensive, as long as they keep your eyes from drying out they're doing their job.

I'd totally recommend the glasses and drops if you can afford it. The protection is definitely worth the investment on the long run as you only have one pair of eyes ;)