Your object isn't aligned with the Cartesian coordinates. You'd like to view it in Edit Mode straight-on, without changing the objects orientation. Press-and-hod the Shift key while pressing the normal viewing keys. For example pressing Shift+Numpad1 will align the view to the object Y-Axis (front-to-back).
See "It is hard to see the "how to" in the context you describe, but here is an approach for rigging the eyes." for better answer.
When Animating the Eye with the “Track To” Constraint, the location of the mesh changes. How do I fix this?