Eyelash serum - does it work? Which brand?

[DelphiniumBlue]

I can't wear mascara, and successfully dye my lashes myself, but it would be nice it they were thicker/longer. I've seen various serums advertised, but do they actually work?
I'm wondering about No7 Lash Impact, but happy to consider other makes if anyone has a recommendation. Thanks!

@DelphiniumBlue Sorry to bump an old thread, but interested to know whether you tried any of these serums in the end, and whether you saw any results?

And only blue eyes are potentially affected.

I don't think rapidlash has bimatoprost in it.

QuimReaper, no I haven't tried the serums, I am a little put off by the changing eyecolour thing. I may still reconsider, though. Jury does still seem to be out!

This is with rapidlash, my lashes are v short usually! No change in eye colour, still the same