Hi, you can get a pair of eyeglasses with prescription lenses as long as you provide your prescription. I know an online optical shop Firmoo.com. They sale eyeglasses including prescription eyeglasses .Hope this helps you.
Most online optical shop sell both eyeglasses frames and lenses. If you want and buy eyeglasses frames only, you will get a pair of glasses frames. Or if you buy glasses frames and lenses, you will get it with lenses. If you need prescription glasses, you are required to offer current prescription when you order it online. Then, they will send a pair of prescription glasses to you so you needn't take it to optician.
Well, online eyeglasses stores can provide you with a pair of glasses. But you can buy frames or lenses from them too. If you a frame at hand or you want to install new lenses with old frame, you can order lenses online. And then ask an optician in your local place to install the lenses for you. If you want to buy the frame to decorate yourself, you can buy the frame only. But I won't suggest you to buy a pair of lenses online because you don't know whether this kind of lenses fit your frame or not. There are some frames that need particular lenses because they have different arc.
If you choose a pair of glasses online, the system will remind you to input your prescription and then they will make a pair of prescription glasses according to your prescription. You don't need to buy a pair of lenses or install the lenses by an optician.
You can get a pair of complete glasses from online eyeglasses stores. Why bother to buy lenses from other optical shops and ask the optician to install them? If you want to buy a pair of prescription glasses, you can add the glasses that you like into the cart. Then there will be a form for you to input your PD and eyesight. After finishing this, you can continue to choose which kind of lenses you want. I think maybe this is the first time you place an order from online eyeglasses stores so you may have this question. You can have a try on Firmoo and you will know this.