Not only in judgements, however, but even in conceptions, is an a priori origin manifest. For example, if we take away by degrees from our conceptions of a body all that can be referred to mere sensuous experience — colour, hardness or softness, weight, even impenetrability — the body will then vanish; but the space which it occupied still remains, and this it is utterly impossible to annihilate in thought. Again, if we take away, in like manner, from our empirical conception of any object, corporeal or incorporeal, all properties which mere experience has taught us to connect with it, still we cannot think away those through which we cogitate it as substance, or adhering to substance, al: that though our conception of substance is more determined than that of an object. Compelled, therefore, by that necessity with which the conception of substance forces itself upon us, we must confess that it has its seat in our faculty of cognition a priori.
Kant's Preface to the Critique of Pure Reason.
He seems to be saying that our empirical conception of a visual sense object necessarily takes up some space: that we can only see things that take up space.
And when Wittgenstein says that:
our visual field has no limits
that we cannot represent the horizon of what we see, is he talking about the same phenomena?
If the limits of the visual field cannot be defined then must it always have the same extent? Is it impossible to "annihilate in thought" our visual field - because it has no limits?