If glasses damage your eyesight especially if your short sighted, why a higher give prescription?

I am very short sighted, My glasses prescription is a -11:50 contacts prescription -10:00. I spoke to a contact lens specialist asking if he believes that glasses can make the eyesight worse. His answer was a yes but he said in my case what can they do as I am so short sighted I cant really see detail properly.
I am not blind just very short sighted. In this day and age you would think that the William Bates exercises would be reserched some more. As it has obviously worked for a lot of people in some cases instantly. The well known fact that our eyes are not permenantly fixed in the short sighted or long sighted mode that you can actually make a short sighted persons eyes worse as the eyes will changge shape with the strength of the lenses. plus glasses restrict the movement of the eyeball. I remember speaking to one lady who said if your eyesight is going to change it is going to change. It seems different optisions have their own ideas.If glasses damage your eyesight especially if your short sighted, why a higher give prescription?
I think its rubbish. I have needed to wear glasses for 15 years and my oriuginal prescription was -0.5 in each eye. Didnt wear glasses for 4 years until I got contact lenses by which time my eyesight was -4 in each eye. So they got worse on their own.
Its the shape of the lens of your eye that causes poor eyesight so I dont see how wearing glasses can affect this, otherwise, surely they would have some up with a lens that corrected bad eyesight?
i'm sorry it don't sound much fun for you!
i don't know anything about this field, but have you looked into the possibility of lazer treatment? i've known a couple of people who have had good results, though i know not everyone can be helped.