THE EXCEPTIONAL LEARNER
11 c ii). Examine blindness in the teaching environment.
The Visually Impaired
Definition of the term blindness
Blindness is generally defined as visual acuity for distance vision of 20/200 or less in the better eye with the best correction. Very simply put a person will be defined as blind if they can see an object that the normal sighted person can see from 200ft at 20 feet. That means that a blind person has to be very close to the object in order to see it (20feet) while the normal person sees it from 200feet.
Blindness can also be defined from the perspective of field of vision. If the widest diameter of field of vision subtends on an angle no greater than 20 degrees, the person is partially sighted. A person with a visual acuity greater than 20/70 in the better eye with correction has low vision but can learn to read large print. The educationally blind refer to those who cannot learn to read print and who must use hearing and touch as the prominent learning channels.
Causes of visual impairment
There are varied causes to visual impairment Infectious diseases like German measles
If the expectant mother contracts German measles during the first three months of pregnancy, the child is likely to be born blind.
Hereditary factors. If the child has a genetic defect affecting chromosomes 14-16 they are born with small or absent eyes.
Accidents and injury to the eyes also cause blindness.
Poisoning caused by the spitting cobra or other chemicals that are harmful to the eyes are known to cause blindness
Tumours, these are growths in the brain which suppress the visual area of the brain can cause blindness.
Problems associated with visual impairment
Children who have difficulty seeing will often hold books either very close or very far from their eyes. Some will tilt the head making an effort to see. The teacher could also notice students with crossed eyes (strabism). These students have eyes that lack coordination in focusing so that they see with each eye individually. Other problems associated with visual impairment are rubbing eyes frequently, squinting, displaying sensitivity to bright lights and or being awkward in games requiring eye hand coordination.
Other characteristics of the visually impaired are:
Problems in mobility: -Whenever they are in new environments they need mobility training so that they can get by independently. In a way, blindness affects speech with blind speaking louder than sighted people. Their speech is slower in rate and lacks modulations. The blind people use less lip movement in articulation of sounds, they also lack effective use of gestures and bodily actions typical of the sighted.
The management of the visually impaired students
There are special materials and equipment that help visually impaired students to function in regular classrooms. These include large print, typewriters, tape recorders, special calculators, the abacus, three dimensional maps, charts, models and special measuring devices. Instructions in Braille are also useful.