Visual Impairment means losses in vision which can be partial or total. Many people often think that when we talk of visual impairment it is solely referring to a person who lives in total darkness. However, not all visually impaired persons live in total darkness.
TYPES OF VISUAL IMPAIRMENT
These are tow major types of Visual Impairment
- LOW VISION: This is also called partially sighted. Individuals with low vision have some amount of visions called residual vision. With some modifications and adaptations, they can read printed materials. Individuals with low vision have visual acuity of 20/70 or less. Most eye clinics use the snollen chart for determining visual acuity.
Visual acuity is the distance the eyes can see, visual acuity of 20/70 means that the child can see at a distance of 20 feet what someone with normal vision sees at 70.
- BLIND: These people may have minimal or no vision. Such people require instructions in Braille to be able to read and write.
They have a visual acuity score of 20/200. A child who is born with visual impairment is said to be congenitally visually impaired and the one who develops the problem later in life is said to be adventitiously visually impaired.
SIGNS / CHARACTERISTICS / INDENTIFICATION OF THE VISUALLY
- EYE CONDITION
- Colour of the eyes frequently reddening
- Tears called cacrimal fluid come from the eyes frequently.
- Unsual blinking of the eye.
- Pupils of the eyes with different sizes.
- Frequent and faster movement of eyeball.
- Closes one eye when there is light
- Frequent discharge (pus) from the eyes
- Pupil in the eyes became whitish
- BEHAVIOUR OF THE INDIVIDUAL
- Frequently rubs the eys
- Frequently bumps into objects like tables, chairs, etc.
- Covers eyes when reading or looking at something
- Difficulty in differentiating between objects, colours, letters
- Skips over words or letters when reading 6. Difficulty in copying correctly from the chalkboard
- Shows sensitivity to light.
- They read materials either drawn closer to or far from the eyes.
- Experiences delays in play skills.
10.Usually copies exercises on the chalkboard from pupils sitting near or close.
11.They usually write with lots of mistaking eg. they reverse letters, write above or below the line.
TERMS IN VISUAL IMPAIRMENTS
|2. HYPEROPIA||–||Far Sightedness|
|3. ASTIGMATISM||–||People with distorted or blurred vision|
|4. STRABISMUS||–||This occurs when the two eyes do not align|
|5. NYSTAGMUS||–||This is characterized by a rapid movement of the eyes.|
It does not allow for proper focusing.
CAUSES OF VISUAL IMPAIRMENT
The causes of Visual Impairment are mainly hereditary and environment.
(A) HEREDITARY CAUSES these are factors which are transmitted from parents or grandparents to their children who also have visual impairment. They include the following:
- THE RHESUS FACTOR
The Rh Factor relates to the inability of the blood group of a fetus to live in harmony with the mother’s blood due mainly to differences in blood characteristics. When this happens, some antibodies from the mother’s plasma attack the antigens in the fetus red blood corpuscles which may end up being destroyed. This tends to reduce the flow of oxygen to the fetus system leading to several problems including visual impairment.
- DEOXYRIBONUCLEIC ACID (DNA)
Life of a fetus begins as a result of the fusion of 23 pairs of chromosomes and all the chromosomes contain the genes. Inside the genes is an important chemical responsible for hereditary traits called Deoxyribonucleic Acid or DNA. The DNA is, therefore, responsible for features such as the Colour of hair, skin, nose etc. It is also responsible for the shape of the eyeball, thickness or thinness of the lens etc. This means that if a parent or some relatives have oval – shaped eyeball, the child may inherit the same thing through the DNA.
When a chi ld inherits the gene for breaking down vitamin A and this gene is an inactive one, then the vitamin cannot be broken down.
The body cannot, therefore, get vitamin A to use. It may affect the child’s vision since the rods which are the cells that enable us to see in the night depends on vitamin A. The child may experience momentary darkness any time he enters a dark room.
(B) ENVIRONMENTAL CAUSES
- MATERNAL MALNUTRITION
Since during pregnancy, food nutrients are passed on from the mother to the unborn baby, any weakness in the mother’s nutrition negatively affects the baby in the womb. For example, if the mother lack vitamin A, the unborn baby may develop night blindness.
During the first three months of pregnancy if the mother takes in any drug in the quinine family, it may affect the child’s vision. The reason is that such drugs destroy the delicate cells that are forming the eyes in the womb.
- MATERNAL DISEASES
When a pregnant mother suffers from diseases like measles, rubella etc during the first three months, the unborn baby’s vision may be affected.
- Treating eye problems with herbs. For example, if a child contracts conjuctive (Apollo) and herbal juice is dropped onto the eyes, sores develop. When the sore heal, they leave scars on the eye including the pupil resulting in visual impairments.
MANAGEMENT OF VISUALLY IMPAIRED CHIDLREN
- Avoid the use of gestures and non-verbal cues such as nodding the head when communicating with them.
- Say aloud what you write on the chalkboard.
- Allow him extra time to complete assignments.
- When you call a visually impaired child, remain where you called him for till he comes.
- Provide tape recorded materials.
- Provide guides, orientation and mobility practice
- Eliminate unnecessary obstacles
- Call pupils by their names.
- Use heavy black marking pens.
10.Allow the visually impaired child to use Braille, if possible
11.Do not leave the room without telling the pupil and always announce your presence when you enter.
12.Pupils working position – the position a child occupies in the classroom should be dependent on his visual competence.