Defects Of Vision And Their Correction
Chapter Name : Human Eye And Colorful World |
Sub Topic Code : 101_10_11_02_01 |
Topic Name : Defects Of Vision And Their Correction |
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Sub Topic Name : Defects Of Vision And Their Correction |
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Introduction
usually when the image of the object forms on retina, but sometimes light rays may fall beyond retina creating defects in the vision.
Pre-Requisites:
Introduction about the eye and power of accommodation of eye lens.
Activity:
See the image formation by ray diagrams in all these defects and observe which lens is required to correct those defects.
Real Life Question:
"Why a person sometimes can't see the objects distant from him?" "Why people wear spectacles?"
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Myopia | A defect of eye in which a person can see the nearby objects clearly but not the distant objects. |
| Hypermetropia | A eye defect in which person can see distant objects clearly but cannot see nearby objects. |
| Presbiopia | An old man can't see the nearby objects properly, this is called Presbiopia. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|
Real life uses :
In making of lens to correct the eye defects such as- myopia, hypermetropia, etc.
Places to visit :
You can to any eye doctor's clinic, where you can know more about the defects of the eye and the methods to correct them.
Practical examples around us
| Examples | Explainations |
|---|---|
| Any person wearing spectacles | These spectacles are used to correct the vision of the eye. |
What you learn in Theory:
When light rays don't fall on the retina, the image formed is not proper. Therefor to form the image at retina we need to use proper lenses.
What you learn in Practice:
There may be some defects in the eye which can effect the vision of the eye. Although these can be corrected by using some special lenses.