Visual Impairment
Eyes are the most important sense organ of the human body. If the functioning of the eyes is hindered or there is a lack of it in the body, then man is deprived of the natural gift of vision. In this situation, the world of a person is limited to his surroundings only. In such a situation, the person starts considering his life meaningless and curses his fate. He starts considering his life a burden on the family and is always suffering from inferiority complex. He starts considering himself different from the society and considers himself worthless. But in today’s scientific era, making rapid progress, scientists have discovered such means through which man can organize his life by increasing the mobility and efficiency of his sense organs i.e. the power of hearing, smelling, tasting and touching.
Definition of blindness- People have had different opinions from time to time to define blindness.
1. According to ancient opinion
2. Educationally
3. Medically
Educationally-
From an educational point of view, even after using all the visual aids, if teaching is not possible even partially, then this condition is called blindness.
Medically-
Medically, the basis of definition of blindness through medical method is Visual Acuity and Field of vision.
Function of the Eye-
The eye is a valuable gift given by nature to humans and all living beings. Its function is like a photo camera. The eye is a special type of optical instrument. The real images of objects in the eye are formed on the retina. The eyelids of the human eye work like the shutter of a camera. When the eyelids of the eye are open, the rays of light coming from the object placed in front are reflected on the sclera. From here the rays are refracted and fall on the retina passing through the aqueous humor, lens, vitreous humor respectively. The image of the object is formed inverted on the retina. The information of the image reaches the brain through the sensory cells of the retina through the optical veins. The brain acquires knowledge directly on the basis of experience.
Vision Defects-
Due to the weakening of the power of accommodation of the eye, the object is not visible clearly and the vision becomes blurred. This type of defect is called vision defect.
1.Myopia
2.Farsightedness
3.Presbyopia
4.Astigmatism
5.Colour blindness
Myopia-
Myopia or Short Sightedness – A person suffering from myopia can see nearby objects clearly, but objects beyond a certain distance are not visible. That is, the far point of the eye comes closer instead of being at infinity. This defect occurs in a person at the age of 10 to 16 years. The rays coming from infinity do not focus on the retina but focus on a point ahead of the retina. Due to this, a clear image is not formed on the retina.
Farsightedness-
A person suffering from farsightedness can see distant objects clearly, but cannot see nearby objects clearly i.e. Such persons keep the book more than 25 cm away to read. In case of farsightedness, the image of a nearby object is not formed on the retina but behind it.
Presbyopia-
Presbyopia- When nearsightedness and farsightedness occur simultaneously, this defect is called presbyopia. Bifocal lens is used to correct presbyopia. The upper part of the bifocal lens acts like a concave lens and the lower part acts like a convex lens. The upper part of the bifocal lens is used to see distant objects and the lower part is used to see nearby objects.
Astigmatism-
A person suffering from astigmatism sees objects placed horizontally or vertically as blurry. This defect is like spherical aberration.
Colour Blindness-
There are two types of sensitive nerves on the retina of the eye, which are called rod and cone cells.The rod nerves of the retina are sensitive to the intensity of light.The eye identifies different types of colours through these cone cells.If there is a lack of cone nerves on the retina of a person or any defect occurs in them, then such a person becomes incapable of differentiating between colours. This disease is called Colour Blindness.Some people are unable to differentiate between blue and yellow; this type of colour blindness is acquired. This type of colour blindness is genetic.Some people are completely colour blind; this is due to the complete absence of cone nerves on the retina or due to permanent defects in them.
2. The eyes remain red all the time and the eyes keep getting infectious diseases.
3. The eye is abnormally rotated and moves unnaturally, or the two eyes are different from each other and look different.
4. Due to visual impairment, there is difficulty in walking and when asked to look at an object, the child is not able to focus properly.
5. You experience difficulty in reading, keep the book too close to your eyes and are not able to perceive small pictures properly.
6. You always complain of headache and always rub your eyes. You pretend to see something falsely.
7. While looking, both the eyes are not able to adjust and use only one eye for looking.
8. Children suffering from visual impairment have awkward eye movements and their eyelids blink equally. This type of eye is called eye blinking movement.
9. Children suffering from visual impairment have a lot of problems in orientation and mobility. Blind children are not able to understand where they are in the environment. They cannot move freely in the environment without help. Retention means where the person is in the environment. Is he in a field, on the road, near a temple or near a school or is he passing by? Blind children are not able to know this.
10. Due to vision defects, children are not able to respond to light. If children do not respond to light or coloured objects, then the child definitely has a vision defect. If a child does not respond to coloured objects at a young age, he should be immediately taken to a doctor and consulted so that he can be treated in time.
11. Due to lack of vision, blind children are not able to adjust with children of their age. They start considering themselves different from normal children and start living separately. Due to this, the language development of the child does not take place properly. Due to being of shy nature, they are not able to talk to others or any object. In this way, there is a problem in adjusting in the society and they remain self-centred.
12. Children suffering from visual impairment keep the book very close to their eyes for reading. They copy in such a way as if they can see properly. They feel that the letters in the book are not printed properly.
13. While studying with normal children in a normal class, instead of copying from the blackboard, they copy from the notebooks of their classmates.
14. They move their head abnormally to and fro to see a distant object. By seeing this kind of movement, it can also be understood that the child has a visual impairment.
15. Children suffering from visual impairment usually feel objects by touching them and keep turning their head in the direction from which the sound is coming.
16. Small children like a new born infant, a child of about one month does not experience anything with the eyes and not showing his reaction towards light is a symptom of blindness.
17. A child of about three months is not attracted towards any colourful object or toy.
18. Headache while studying or working with eyes for long hours, etc.