Being nearsighted, having an older, weaker pair for using for close work like you are doing is ideal.
There is nothing wrong with that and can't do any harm...and is bound to be more restful than using your full prescription.
Just about all nearsighted people should have a weaker pair laying around for things like that.
You have too much astigmatism to go without anything, so what you are doing is perfect.
Source(s):
Optician