If you want to - go for it
ask yourself why? What made you change? Do you know what an optom is have you seen what they do in a day?
I know you’re in the middle of exams right now, but I would suggest doing work experience, as you don’t want to make a quick decision which you may regret. Just phone up opticians and see if you would be able to shadow the optom (aim to do this before clearing opens)
Often when people do this they are able to get an insight and be like nah not for me or yep defo for me.
if you go on to ucas type the name of course and click show vacancies or something you will be able to see which unis are accepting applications
Hope this helps, but I want to remind you focus on the present (makes sure you smash those exams, and make sure you are mentally well as mental health is the most importantly wealth)