What is the muscular structure located behind the cornea in our eye called?

Which part of the eye controls the amount of light entering it?

When blue and green light overlap,what color does that region appear?

$A$ student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his textbook. Which of the following statements is correct?

$A$ 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.

Presbyopia is a type of far-sightedness.