Final answer:
The diffraction of light by the pupil limits the ability of our eyes to resolve very fine details by causing spreading and blurring of the image.
Step-by-step explanation:
Diffraction limits the resolution in many situations, including the acuity of our vision. When light passes through the pupil, which is the circular aperture of the eye, it spreads and blurs the image due to the diffraction-like spreading of light. This is caused by the limited diameter of the light beam. As a result, diffraction limits the ability of our eyes to resolve very fine details, making it option 1) the correct answer.
The diffraction-like spreading of light due to the limited diameter of the pupil, which serves as a circular aperture, is responsible for a fundamental limit in the resolution of our vision. Given that light passes through this aperture, it undergoes diffraction which causes it to spread and blur the image, much like light passing through any aperture or lens with diameter D.
This effect of diffraction limits the resolution of any optical system whether it is the human eye or a telescope with finite aperture size. The diffraction of light by the iris effectively sets a limit to the eye's acuity, thus the ability of our eyes to resolve very fine details is somewhat restricted.