Nope, you can't change it to double. You can cast a double to var using explicit type casting but then you had a var and not a double meaning that you are still limited by the range of a var.
Btw, just for your interest, a double is in Lite-C a 32 bit floating point variable, not a double precision floating point.
Shitlord by trade and passion. Graphics programmer at Laminar Research. I write blog posts at feresignum.com