u/RabidLiger

I've been the advisor for my local university Pre-Optometry Club for 2 decades.
Here's a list of my observations regarding the OAT:

• Meant to measure basic knowledge and how well you comprehend the science part of your undergrad education.
• You can major in anything & just take pre-reqs, but Bio/Chem majors will have the upper hand in scoring well on the OAT.
• There's not a passing grade (like NBEO), so don't get hung up on achieving an exact score. (low score will make acceptance more difficult, but its just 1 factor of many).
• An OAT booster/prep course is worth it, especially practice tests. Get one, and complete all parts of it! (too many get one and only partially complete the course).
• IMO, take it no more than 2 times. Additional attempts rarely result in significantly higher scores and you spend too much time/resources that could go towards making other parts of your application stronger. If you struggle with the sciences, you will not score high, regardless of cramming/prep courses.
• DON'T take a gap year, just for taking the OAT. You'll do just as well by taking the test when you're in the middle of your science course work. Although gap years are the current flavor of the day, IMO, there just are not many justifiable reasons for delaying your professional education for a whole year & a lot of the application process is tougher if your not currently enrolled (ie getting LOR).
• The Harsh Reality: The OAT is by far the best predictor of how you'll do in optometry school, and especially passing the NBEO exams. It's not the ONLY factor,, but take it seriously that if you cannot do well on the OAT, odds are, you will struggle, and possibly fail. It's not enough to just WANT to be an optometrist. Kind of a brutal statement, and there are those who defy the odds, but go into it with your eyes open.

Saying this, its just my general opinion, & I don't know you specifically, but coming from helping 100+ get into optometry school (and helping others pivot to something else).