[Dyerryjex]

Mekhet, I could be wrong (after all it's been a while since I read Robert's book)- perhaps you can tell me what page it's on- but if my memory serves me right, when he talked about asking for sight, he was talking about when you're already projected and are blind.
Astral sight, (that is, seeing through eyelids while completely awake and in-body) in my experience is a rare thing, and often a preprojection symptom. It is best achieved in the dark with maybe a little dim light (because light 'turns off' the pineal gland) in deep trance. So if you're doing it during the day, make sure it's dark enough.
I do agree that asking as an affirmation to get it is as good as anything else (because your Higher Self knows what's best) but the physical conditions have to be optimal too.
Hope this helped-some.