In optometry, particularly at City Uni in London, they take several mature students, and ones with non-standard qualifiations.
I know of students who had an open university degree being admitted, as well as one with a geography degree. Also, several DOs (dispensing opticians) gain amission every year.
So some of your options are:
1. Do an open university degree - a subject that would help you in the optometry course would be better - the subjects in the 1st yr of optometry usually include general anatomy and physiology, dispensing, physical optics (branch of physis), visual optics (optics in relation to the eye), etc. o choose your subject wisely.
2. Join the dispensing opics course which is easier to get into than optometry, as a steping stone e.g. at Dame Alice Owen Building on Goswell Road in London EC1 (used to be in Binhill Row near Liverpool St yeats ago) or at Anglia College (I believe they have management module included).
Good luck!
M