I ended up with Zeiss glass in my glasses, waste of time. They seem to get dirty quicker. I was sort of "conned" into it at the time.
I said the basic glass, so they put in the basic Zeiss glass. I was happy with BK7, but they cost less. Complained to the optician chain - never went anywhere.
These days they are almost certainly going to be plastic. I had glass but opticians steer away from it now, plastic is I suppose easier and cheaper. When I asked for glass I was told "Not sure our glaziers can handle that", my reply was "Then they are not glaziers then are they?"
Mine are best described as close to useless for the sky. Eventually worked out why.
They will measure your eyes and determine the new lens required, usually for infinity.
Then they add in an amount for "close" use - TV, PC screens etc.
But that close use detracts from the initial which is/was for infinity - or a few lightyears distance.
The idiot on mine added in far too much, so detail of far stuff is lost. You do notbwant to know what M45 looks like to me at this time.
The added thing is termed "Reading Addition".
A previous precription added in 1.5, the last one added in 2.5 and 2.5 is way too much.
So if you want the sky that Reading Addition needs to be low or lowish.
The 2.5 they threw in for mine means I cannot clearly read a number plate at more the 75 feet - that is where it becomes hard work. Utterly stupid bunch. And to add insult to injury to read I do not wear my glasses as for close work I don't need them. So I read a book without glasses at the eyes rest point and all is comfortable. I use this laptop without glasses also. So what reading addiition?
Guess the fun at my next eye test. Which will have to be soon also.
You may want to think of something that passed through my mind: Get a good test and presecription for what you want, get an inexpensive set made, or expensive, then via the internet visit the Glasses Direct site and purchase a set or two from them.
Idea is that if the prescription is good then 2 sets from them can be used for the night sky. That way you have extra sets. My thought being splatting plastic lens on to eyepiece rubber has to damage them eventually. So a couple of almost "throw away" sets makes possible sense. But you need to get the prescription right first, and that means something on your nose to look through.