Isn't the O.D./Ph.D. program the same as the O.D./M.S., except you need a couple of extra years to earn the Ph.D. (whereas the M.S. is granted after four years, alongside the O.D.)?
MS students take one extra class during each semester and spend I believe either one or 2 summers doing research.
For PhD, its much more difficult as you need to be involved in research throughout the duration of the year in addition to extra classes. Not only that, but there is some kind of I don't know how to call it 'situation?' where you may not finish your OD or PhD in 4 years. But in fact, could take you a couple of extra years to finish up both programs.
Because think about it. OD is a degree in an of itself and obviously requires you to be a full time OD student. PhD is the same sort of business. So its kind of like that how to be in 2 places at the same time kind of thing.
Edit: from the SUNY site:
"The ability to obtain both the O.D. degree and the Ph.D. degree concurrently in 6-7 years."
That doesn't mean that after 4 years you are an OD and you finish the PHD in the remaining 2-3 years. It means you will finish up both degrees in a 6-7 year period.
Anyways, as was stated above, unless you really want to teach (which I don't even think all the clinic instructors have PhDs), there really isn't all that much benefit to getting a PhD let alone an MS.
I guess it would look nice hanging on your office wall though.