Figure 2. The effect of distance on the field of view. Reflected light from from three points on an illuminated retina emerges from the right hand eye in parallel. By the time the three beams leaving the eye have reached the observer's eye on the left, they have completely separated, so only the centre beam (green) enters the observer's eye on the left. Thus, the observer can't see the parts of the retina where the blue or orange beams come from.
To see all beams simultaneously, the observer must move to where the beams can enter their pupil. You can see where this occurs by dragging the left hand eye closer. (Note that the three points on the illuminated retina are very far apart, so you have to get unrealistically close to see them. In reality, you could never get this close, so your field of view is more restricted.)