The human eye can focus on objects at different distances by adjusting the focal length of the eye lens. This is due to

$A$ virtual image cannot be focused on a screen. Yet when we see a virtual image,we obviously bring it to the screen that is the retina of our eyes. Is this a contradiction?

Which part of the eye is responsible for changing the focal length of the eye lens by adjusting its thickness?

Name the outermost layer of the eye. What is its function?

In the eye of a person suffering from myopia (nearsightedness),where is the image of a distant object formed?

$A$ person with defective vision is unable to see objects nearer than $1.5 \ m$. He wants to read books at a distance of $30 \ cm$. Find the nature, focal length, and power of the lens he needs in his spectacles.