Return them to your optician - if they are surface scratches, they should be able to grind them out without damaging the lense. It is a specialist job, don't try this at home!
there is something that you can buy on the high street that you knid of paint onto glasses and it fills in the scratches. no idea what it's called thou so i'm not much help really am I?!! Optician should be able to sort them out for free thou.
Scratches cannot be ground out at an opticians. If your lenses are coated it may be possible to strip the coating off and this might get rid of the scratches.
(Providing that the scratch hasn't gone straight through to the lens material)
If it's just a single vision lens, then depending on your prescription they may be able to put a new lens in for you on same day, which won't cost all that much.
A hard coated lens does help reduce scratches but does not make them indestructable.
Before you try any of the above, I've been told by a watch maker that to reduce small grazes/scratches from glass use Duraglit which you can buy form the likes of Woolworths, or any good Cobblers shop. It worked on a rather expensive watch I have...