Care of the Human Eye- Physics Guide for Class 8
Information about Care of the Human Eye
Title | Care of the Human Eye |
Class | Class 8 |
Subject | Class 8 Physics |
Topics Covered |
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Precaution for the Eyes
It is our eyes that allow us to see and interpret the shapes, colours and dimensions of different objects in the world. Our eyes are, therefore, a great asset to all of us. We, therefore, need to take proper care to protect them and keep them healthy.
The following precautions have been suggested to ensure the health, care and proper functioning of the human eye.
- Have a regular check-up. If so advised, use the correct spectacles.
- Never look at the sun, or any other powerful light source, directly.
- Have sufficient light in the room when you are reading, writing or watching television. Poor lightning in the room causes eye strain.
- Try not to spend too much time looking continuously at the computer screen, or television. It can cause eye strain.
- Eat a balanced diet having lots of fruits and vegetables. Lack of vitamin A, in the food, is responsible for many eye problems including night blindness.
- Gently wash eyes frequently with clean (potable) water.
- Know your family history. Some of the vision problems may be inherited, i.e. they may run in the family.
Visually Challenged Persons
It is difficult to 'imagine the world' without a pair of functional eyes. It is, however, an unfortunate fact that many amongst us, including children, do not have this unique gift of nature. It is, however, now possible for them to bravely face this challenge by effectively overcoming their limitations and to lead a (near) normal life. Such brave and courageous visually challenged persons, deserve our appreciation and full support for their courage and conviction.
- Vision problems may be due to some illness, such as diabetes, glucoma, cataract or vitamin A deficiency.
- They can also be due to genetic or inherited problems (the problem gets transferred down to kids from parents through their genes).
- In some unfortunate cases, some persons lose their vision due to some accident.
- Visually challenged person can either have limited vision (partial loss of vision), or may have a complete loss of vision.
- Hence, all visually challenged persons cannot be treated alike. Their individual problems and requirements need to be taken into consideration.
- Most visually challenged persons have a better sense of touch, smell or hearing than the normal people. Such persons try to identify things by developing their other senses more sharply and putting them to effective use.
Help for Visually Challenged Persons
Modern technology also helps them to further develop their capabilities. The vast majority of these people (with partial/complete lack of vision) can be helped to function at a higher level with use of additional resources/aids.
These resources/aids can be of two types:
- Non-optical aids
- Optical aids
1. Non-optical aids
- These often include:
(i) tactual aids (using sense of touch; the visually impaired can learn to read and write by using a special touch system called the Braille. This system makes use of raised dots (put on a paper) and
(ii) auditory (using sense of hearing) aids include audio cassettes, tape recorders, audio CDs, audio books. - Other electronic devices (like computer/calculator/closed circuit television) make use of software programmes that can transfer 'text files' into sound.
2. Optical aids
- These include lenses and telescopic aids.
- While suitable lens combinations are used to rectify visual limitations, the telescopic aids can help to view class demonstrations and the blackboard.
Braille System
The most effective resource for visually challenged person is the Braille.
- Louis Braille, himself a visually challenged person, developed a system for visually challenged persons and published it in 1821.
- The present system was adopted in 1932. Braille is a coded language based on a logical system.
- There are Braille codes for common languages as well as, mathematical and scientific notations. Many languages (foreign/Indian) can be read using the braille system.
- Braille system has 63 dot patterns or characters. These patterns, when embossed on Braille sheets, help visually challenged person to recognise words by touching.
- To make them easier to touch, the dots are raised slightly. Each character has to be memorised.
- Braille text can be produced by hand, or by machines (printing machine/typewriter).