With a wide range of shapes, sizes and colours, finding the right pair of glasses can take time.
But this means companies may also have to overstock to provide the wide selection of products customers expect.
So could face scanning combined with 3D-printing change how we buy glasses and help move towards a more sustainable model?
BBC Click’s Lara Lewington visits one of the opticians offering the technology to find out more.
See more at Click’s website and @BBCClick