Similarly, you normally don't see any imperfections/dust specks on your cornea - but you will if you look into a very narrow (0.1-0.2 mm) beam of light (e.g., w

Similarly, you normally don't see any imperfections/dust specks on your cornea - but you will if you look into a very narrow (0.1-0.2 mm) beam of light (e.g., when using a telescope pushed to a very high magnification = very small exit pupil [1]). [1] https://en.wikipedia.org/wiki/Exit_pupil https://en.wikipedia.org/wiki/Exit_pupil