There's a shop were I usually buy mt glasses. My last glass which had a very sturdy and good looking frame with thin plastic lens of thickness index(T.I.) 1.5( very thin) was around Rs.2,600/-. This time around I placed an order for a similar frame, but the lenses which have a thickness index of 1.5. But the glass is really thick. Now I entered into an arguement with the shop-assistant, saying this isn't 1.5, because my last one was thin and my power hasn't changed. Though I have the bill, the thickness isn't mentioned.I have to end up paying Rs.3000 bugs for the present one. He says that the old one is 1.6 (T.I.). I m sure it's 1.5 T.I. What should I do, bargain for a replacement of the lens or buy the same lens ?