I wouldn’t recommend buying from a market stall, the vision in both eyes might be different like mine is,. I use Pattaya Optical on Pattaya Klang who have an Optometrist, not the cheapest but a proper eye test.,Eye test is free if you buy spec,s great selection of frames. I have also used Euro Optics in Royal Garden Plaza, she is also an Optometrist, not a great selection of frames though.