I would not necessarily that because you are in the medical corps, that you will be found fit.
I too was referred for a visual field defect (homonymous hemianopsia) as an unfitting condition. I know for a fact that I could have continued to work in my field since I was already performing duties above standard with the condition for four years.
In my case, the standard was AR 40-501 Chapter 3-16 (c).
Hemianopsia, of any type if bilateral, permanent, and based on an organic defect. Those due to a functional neurosis and those due to transitory conditions, such as periodic migraine, are not considered to fall below required standards
So you were found unfit? I have homonymous quadrantanopia and it is the entire bottom right, so an 90 degree angle, if that makes sense? Then I do have residual tumor left as well. From what I was gathering it looks like it will be 30%, 20% for the vision and 10% for the tumor since there is residual left.