I can give you the pros/cons of dentistry. I don't know anything about optometry except increasing debt and stagnant/shrinking pay. Optometry doesn't seem worth it if they are stuck in the 90- low 100's for pay.
Dentistry pros: Money, hours, lifestyle, much higher earning potential, more entrepreneurship/ownership opportunities, many subspecialties of dentistry,
Dentistry cons: Increasing student loan debt, working in a small space, periobreath, stagnant insurance reimbursements, harder to get into, tiring on the hands.
You can do both, but I think you have to answer this basic question: Do I want to make lots of money and am I willing to work hard for it AND/OR do I want to be fulfilled in life? If the motivation is money and slogging through something you might not have your heart in is something in the works, then consider dentistry. If your true calling is optometry and the money doesn't matter, do optometry. If money matters but you love optometry, then you either have to find a way to make a killing in optometry or choose dentistry (if you only had two choices).