*Why I am paying in PKR though the prices are in USD?
As per the rules of "SBP" State Bank of Pakistan online stores and payment processor can only accept payments by credit card in local currency which is Pakistani Rupee (PKR Rs). The prices shown in USD are for guidance purposes so you could know at what USD price you are buying any product from Ortho Class.
*How does it all works?
When you pay in PKR you are actually paying in USD. The only difference is that you are converting USD to PKR because we have to follow the Currency Conversion Act issued by SBP for accepting any payment via Credit / Debit Card online.