Bear in mind that optometry school usually involves the assumption of tens of thousands of dollars of student loan debt. There are 17 Schools of Optometry in the United States that lead to the O.D. degree.
Most students apply to more than one school.
Several optometry schools are in the Midwest, but none are in Wisconsin. You should pick the schools that interest you and, from that school listing site, visit individual school web sites for school-specific information on admissions procedures. The OAT is currently offered in February and October of each year. You do not have to be a Biology major to be a Pre-Opto, but this list of required courses for admission to many optometry schools is usually long enough to justify a Biology major. Also, having had some biology education prior to optometry school makes optometry school itself a bit easier, I am told.