What is the least distance of distinct vision for the normal eye does the above distance increase or decrease for long sighted eye give reason for your answer with diagram?

(a) Write the function of each of the following parts of the human eye:

Cornea; iris; crystalline lens; ciliary muscles

(b) Millions of people in the developing countries of the world are suffering from corneal blindness. These persons can be cured by replacing the defective cornea with the cornea of a donated eye. A charitable society of your city has organised a campaign in your neighbourhood in order to create awareness about this fact. If you are asked to participate in this mission, how would you contribute in this noble cause?
(i) State the objective of organising such campaigns.
(ii) List two arguments which you would give to motivate the people to donate their eyes after death.
(iii) List two values which are developed in the persons who actively participate and contribute in such programmes.

a) The function of:Cornea: When light enters the eye, most of the refraction occurs at the surface of cornea. Iris: It is a dark, muscular diaphragm that controls the size of the pupil. Crystalline lens: Helps in the finer adjustment of the focal length required to focus objects at different distances on the retina. Ciliary muscles: The lens becomes thin when ciliary muscles are relaxed thereby, increasing its focal length. Thus, we are able to see the distant object clearly. The ciliary muscles contract, when we are viewing objects nearby, increasing the curvature of the eye lens. Therefore, the eye lens becomes thicker and focal length decreases. This makes it easier to see the nearby objects clearly. b)i) The objective of such organisation is to light up the life of a blind person by donating eyes. the objective statement will be, 'Enlighten the life of Blind'.ii) The arguments are:1. We have enjoyed our life by seeing the beauty of nature. Then why not give the same pleasure to the blind. Pass on your gift of vision to the needy and do a charitable deed.2. Age group of a person or sex does not matter when it comes to donating eyes. If a  person uses spectacles or underwent surgery for cataract, can also donate eyes. A person suffering from any kind of communicable disease cannot donate eyes.

iii) Social welfare, awareness, charitability are some of the values that is developed in a person who actively participate and contribute to such programs.