Hi mgro33 and tatispice,
This is my experience for preparing the OAT. I used primarily my class notes and this MCAT ExamKrackers by Jonathan Orsay. It's a really good prep book for whether you are taking MCAT or OAT. The book is really easy to understand and they only put important info so you are not wasting your time. However there are 5 Examkracker books(bio, math, chem, orgo, and physics) and each has its own problem book. I only bought the physics and orgo ones and I found them extremely useful because I scored high on MCAT and the OAT(12 science on MCAT, 370 physics and 390 orgo on OAT)
2 weeks before the OAT, I bought a mock OAT cd-rom to test myself. The cd rom is called: OAT-Optometry Admission Test Sample Exams : TopScore Pro for the OAT by ScholarWare. It was very useful for me and the questions are similar to the ones appear on OAT. The only con about the cd is its reading part. Since you have to practice on computer you cant really simulate like you are taking the actualy exam(on paper).
I did borrow the OAT prep book by Lippincott, Williams and Wilkins named "preparing for the OAT and it wasnt too good. Some of the questions are out of the OAT topic but a few people I know said they only used this book.
I think the best way to know how you can prepare the OAT is to take the OAT practice in the OAT booklet. If you have problem on a specific subject then focus on that part. I didnt study a lot for bio, math and chem because I am good at it.
Last thing is the only book above i would suggest is the examkracker book. It really boost my score. I had a C+ in Organic1 and B+ on Organic2 but I scored 390 using that book.If you have any more question you are welcome to ask/email me.
Study hard and happy holidays!