I believe that there is much BS in this field, and I don't think that drops sepcifically advertised for computer related ailments work better than other, maybe cheaper, products.
As far as I can see, there are two effects related for acute, short term strain on the eyes.
1) One tends to blink less when staring on a computer screen, which leads to dry eyes. Any droplet that can reduce dryness is helpful here.
2) Since the computer screen is at a fixed distance which is way closer than the distance the human eye has evolved to watch, one strains your eye muscles for focusing. As far as I know, there's no droplet that can help you here. The only way to relief is to follow workplace guidelines: Good monitors, right lighting, try to move your eyes away and focus on different distances to get relief. I also found that good sub-pixel-smoothing (font smoothing etc.) is very helpful -- I found that the slight blur does not force my eye to focus, as pixel-sharp fonts do, so I can work with slightly defocused vision, which puts much less strain on my eyes.