What are the Refractive defects of vision? How are they caused? How can
they be cured? Class 8 science chapter 16 Light
Answers
Answer:
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 appropiate 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 a needy after death, printing posters to aware people about it.
Answer:
Vision problems such as myopia and hyperopia can be corrected with lenses that help focus light on the retina. Myopia is corrected with a concave lens, while hyperopia is corrected with a convex lens.