(a) List three common refractive defects of vision. Suggest a way of correcting these defects.
(b) About $45lac$ people in developing countries are suffering from corneal blindness. About $30lac$ children below the age of $12$ years suffering from this defect can be cured by replacing the defective cornea with the cornea of a donated eye. How and why can students of your age involve themselves to create awareness about this fact among people?

(a) Three common refractive defects of vision are :

1. Myopia, also known as near-sightedness and short-sightedness, is a condition of the eye where the light that comes in does not directly focus on the retina but in front of it, causing the image that one sees when looking at a distant object to be out of focus.

2.Hypermetropia - A defect of the eye that causes light to focus behind the retina instead of directly on it, resulting in an inability to see near objects clearly

3.Presbyopia - is part of the natural aging process of the eye

1.Myopia is corrected by using a concave lens of appropriate power

2. Hypermetropia is corrected by using a convex lens of appropriate power.

3. Presbyopia cannot be cured. Instead, prescription glasses, contact lenses, reading glasses, progressive addition lenses, or bifocals can help correct the effects of presbyopia.

(b)Awareness can be spread by - Donating the eye to the needy after death, printing posters to aware people of it.