I can give you a little more insight into both the fields of medicine and dentistry, they were both careers I was interested in before I made my decision to go on to optometry school. The reason I did not choose medical school was basically because I shadowed several MDs, both GP and surgeons and I asked every one of them if they had their life to do over again would you still go to med school. Every single one said absolutely not. That spoke a lot for the profession as far as I was concerned. If you didn't have to pay outrageous malpractice insurance and worry about sue happy patients and attorneys it would be a much better career.
Dentistry was much more appealing with good work hours, you can own your own business, and prosper monetarily; however, the main turnoff for me was that after school you will be in debt some $250,000 to $300,000 (for me anyway) and if your parents aren't dentists what are you going to do? The banks are not very keen on loaning you several hundred thousand dollars to start your own practice when you are that far in debt. I know quite a few new graduates who are in this situation and they are working at places like Sears making far less than they should. That wouldn't be that big of a deal if you could easily get a job right out of school, but most dentists have their own practice which leaves new graduates with not many options out of school (or at least in my state). But it is a good profession for the right person, and if you have ample funding it is even better
I choose optometry because right out of school you will most likely have many jobs to choose from, and the average indebtedness for some private schools is around $90,000 (SCO). And let's face it, optometry is a great field, virtually no malpractice, you most likely will not kill anyone, and the patient attitude is sooo much better than that of dentistry. No, you probably won't make as much money as MD or DMD's make, but so what? If you enjoy your job (as all the optometrists I've spoken to do) and make a good living, then you'll be happy with your choice. I encourage you to ask around your area, talk to new graduates from all the fields you are looking into and get some advice from them. As for me, I love optometry!!