Question

State the function of each of the following parts of the human eye: 

(i) Cornea  (ii) Iris 

(iii) Pupil (iv) Retina 

Millions of people of the developing countries are suffering from corneal blindness. The disease can be cured by replacing the defective cornea with the cornea of donated eye. Your school has organized a campaign in the school and its neighborhood in order to create awareness about this fact and motivate people to donate their eyes after death. How can you along with your classmates contribute to this noble cause? State the objectives of organizing such campaigns in schools.

Answer 1

I. CORNEA – The cornea acts as protective layer through which light enters our eye, it is transparent. Most of the refraction occurs here. 

II. IRIS – It is dark and behind the cornea. It controls the size of pupil according to the light entering with intensity. It determines eye colour. 

III. PUPIL – It checks the amount of light entering the eye and changes its size with the help of iris accordingly. 

IV. RETINA – The function of retina is to receive the light focused by the eye lens or crystalline lens and convert it to electrical signals that will be interpreted by the brain through optic nerve. It has enormous number of light-sensitive cells.