First of all, you need to find a reliable online optical shop so as to get good prescription glasses.
Second, you shall take full advantages of the sellers. Now, most of online shop provide Virtual try on System, you can use it to help you choose the best look eyeglasses frames.
Third, you can buy their eyeglasses frames with lenses. And online shop will require you input an prescription. You can follow his hint step by step to continue the order. If you have any question about the order, you can contact their customer services and ask help. Hope this helps.
If you have your prescription, it is easy to order glasses online. First, you should find out the style of the glasses you want to buy. Then select the material of the lens and frame of the glasses you need. Then can begin to order them. During the process, you are required to fill a form with your prescription. Just follow the steps and then you will order your prescription glasses online easily. If you can't understand this, you can contact their customer service.