Avoid multi-focals with very curved lenses as the distortion and reflections at night are hard to deal with. Bright approach lights through a windscreen which has reflections from inside the cockpit and wrap around lenses aren't a good mix. I have a seperate night pair with relatively flat lenses which doubles as my spare, these are the ones I use when I do my medical.
It might be worth going to a CASA approved opthamologist rather than a high street opticians.