HOI AN OPTICIANS
Many expats have prescription glasses made in Hoi An. If you do not have a prescription, it is not a problem. They can work out your prescription from existing glasses or they can do an eye test. Generally, the eye test is free. The turnaround process is quick. Mine (copied from existing glasses) were made in under an hour. It could take a couple of days however if they have to send away for a specific type of lens.