If the retina were a mirror, would it be a convex or a concave mirror if the person is nearsighted?

Question

I know in order to correct a nearsighted vision, concave lenses are needed. But the question is for a person who is nearsighted, is his/her retina convexing or concaving?

Answer 1

Remember is correct. Think of the retina as the movie screen. The part that causes near- and far-sightedness is the lens that projects the movie onto the screen. If it's out of focus, it's either too close or too far from the screen.

So nearsightedness (myopia) and farsightedness (hyperopia) are caused by the shape of the eye, not the shape of the retina.

Answer 2

The Retina is ALWAYS concave.  

The problem is where is the focus of the lens?  

The eyeball can be too long so the focus is in front of the retina or too short so the focus is behind the retina.  

Also the lens itself can be a problem if it has lost its ability to focus for close or distance.  

Lastly, you could have some corneal damage which changes the focus,  which is where they got the idea for Lasik and the other corneal shaping procedures.

Answer 3

To pick up on rememberthecole's answer:  If the eyeball is too long, that means that relatively, the lens (double convex) is not convex enough; and if the eyeball is too short, the lens is relatively too convex.