I have trouble seeing distant things and have myopia. Thus I prefer glasses with my prescription number (which is both cylindrical and spherical). I want protection from UV rays as I am going to spend some time during this trek which would be crossing 5000m. Can you suggest me specific kind of glasses that could help me. I read photochromatic lens might not be good enough. I don't want to change glass every time so I am looking to explain my local stores to get me a glass with specific properties that have my prescription for myopic vision.
There are several options
Goggles that fit over you prescription glasses (Commonly referred to as "Over the glasses" or just 'OTG'.) - probably the cheapest solution, used successfully by many people.
Contact lenses are available for all sorts of prescriptions now days and could be worth considering.
Prescription Sun Glasses - good wrap around sports len's will provide enough protection for 5000 Meters. These are expensive, but will be usable for other activities other than snow sports
Prescription lens in Googles - best solution for above the snow line but not cheap and not as versatile as prescription sun glasses.
Talk to to your optometrist as he will be able to offer the best advise for you.