We on TSR and any others you ask can only offer so much help mate.
It is first and foremost; a personal decision. What is it you want to do, as in what excites you or interests you, what about optometry appeals to you and is there any things in particular you want to experience or be a part of both in the near future and later on? After you come up with some answers of basic things like that which are very important to you on a personal level you can then look into industries and career types, in your case healthcare I suppose?
Btw often times maths is considered as a science substitute and also there are many foundation courses for the other science/engineering type degrees as it's quite in demand stuff.