What do you mean by really low? I don't know of many who get in with less than at least a 310.. but I'm sure it's possible somewhere. I guess it all depends on what your GPA is also.
I know a few who got alittle less than a 300 on the OAT, and still got into OD school. However, if you get a really low score, admissions will ask you to retake the exam.