When your iris changes in size from light why does does the area we can see not change?

Question

When your iris changes in size from light why does does the area we can see not change?

In: Biology

Answer 1

Short answer: because light travels through the center of the lens and focuses it onto a small point. You can cover up the edges of a magnifying glass but still see the same image magnified.

Closing your iris is analogous to this. The center of the lens still has the same field of view, thusly it focuses that field of view into the retina (and we perceive it as such).