Diffraction limite of the human eye

[oldspice1212]

Calculate the diffraction limit of the human eye, assuming a wide-open pupil so that your eye acts like a lens with diameter 0.8 centimeter, for visible light of 500-nanometer wavelength.

Is there a formula for this? There are two other parts to this question, but if I get this the others won't be hard to get.

 

[oldspice1212]

Nvm I got it diffraction limit ~ 2.5 * 10^5 therefore you multiply it by wavelength of light/ diameter of telescope getting 16 ".