I'm not sure but Optical Express were doing a free eyetest voucher if you want to get them done sooner and you can't get a free over 60 one if you're allowed to use it like that.
I used one the other week to get my prescription rechecked before changing my glasses after my free work voucher eyetest showed my prescription has improved a lot - wanted to make sure before shelling out and have another check on my eyes being dry.



