Hi, can someone explain to me how the yellow NHS vouchers work, my little boys eyes were tested (+7 and +3) in January and he got a voucher we used in Boots to get glasses. Hes has two further funded eye tests through Boots and his prescription has changed (+5 and +3) they changed the lenses for free after the first test but for the second it stayed the same so he's been in the same glasses just with different lenses since January, does this seem right? We were speaking to a private opticians and they said he should be issued a new yellow voucher if hes had a funded eye test? So confused