I believe so. Any spell that lists a Precision rating (less than 100) also benefits from the caster's precision, which in turn benefits from Eye of Aiming.
Eye of prec improves the wearer's prec by +5 (Eye is +8 but corresponding eye loss gives -3).
This increased prec is useful for anything that use Prec rating, ie missile wpns and non-100 prec spells.
Try it on an Anathemant Dragon and see the result !
Why do you say use only with precision 100 spells?
Because if you use an artifact eye that has no precision bonus you get -3 to precision and have trouble hitting anything if you don't use precision 100 spells.