I would say something along the lines of you aren’t going to make any decision on glasses today as you need to think about it. Take the prescription, order online and the optician won’t see you again for two years.
With the price of glasses online you can order a few pairs. I order an identical pair with medium tint to act as prescription sunglasses.
I was thinking of trying polarised, but I am working mostly in dark hours at the moment, so won’t bother.