What you are describing is strabismus - a 'squint' - ie. one eye, (usually), either turns inwards, or outwards. Sometimes, people can have a very slight squint without knowing about it, while for others, it is very noticable cosmetically.
'Phoria' means that the eye(s) have an INWARD crossing tendency, which is controlled with effort.
Prism trials are normally carried out to determine the strength of prism required to correct the squint. (A prism can be slotted onto glasses, usually for trials, but can be ground in for a permanent solution).
I don't know what the CAA limits are, (correction - I didn't, until you duplicated them on your posting!), but they will be looking to ensure that: 1) You do not have, or are likely to develop, diplopia, (double vision) 2) You can attain fusion - i.e. both your eyes can look directly at an object, and your brain 'fuse' the two retinal images into one single image.
Obviously you were not aware of this condition, so that in itself would suggest that it is mild, so hopefully, you will be OK regarding the medical
FD