2.1 Definitions of Visual Impairment

With reference to
Hong Kong Review of Rehabilitation Programme Plan (1994/95-1998/99) Section 5.1, the definitions of visual impairment are as follows:

Total Blindness

Persons with no visual function, i.e. no light perception.

Low Vision
The mild low vision group - people with
visual acuity* from 6/18 to better than 6/60

The moderate low vision group - people with visual acuity from 6/60 to better than 6/120
The severe low vision group - people with visual acuity of 6/120 or worse or people with constricted
visual field in which the widest field diameter subtends an angular subtense of 20 degrees or less, irrespective of the visual acuity.


2.2 Objectives of the Education of Visually Impaired Children

The objectives of the education of visually impaired children are:

(1) To develop the physical, mental and social potentials of these children to the full.
(2) To develop independence, self-reliance and competence in these children.
(3) To develop life adjustment and self-care skills in these children so that they can become well-adjusted and independent individuals in society.

2.3 Curriculum Areas

The curriculum for visually impaired children aims at developing academic and functional skills in these children. The curriculum areas therefore include academic and cultural subjects, technical and practical skills, functional and self-care skills, etc.


2.4 Learning Difficulties of Visually Impaired Children

As visual impairment imposes limitations on the children in such aspects as mobility, the range and variety of experiences and the ability to cope in different situations, visually impaired children may encounter the following learning difficulties:

2.4.1 Difficulties in Perception and Concept Formation

Severely visually impaired children may suffer from delay in cognitive development, especially in perception and concept formation. These children may therefore have difficulties in obtaining visual information and in forming perception about people and things and what is happening in their environment. These difficulties will prevent them from consolidating their perceptual experiences into concepts. They have to obtain information through other sensory modalities, e.g. auditory, tactile, olfactory, etc. and the information obtained may be limited and confusing.

2.4.2 Delay in Physical and Motor Developments

The physical and motor developments of visually impaired children may be affected by their difficulties in
spatial orientation. They may have poor postures and poor hand control. They may easily bump into furniture, equipment and people.

2.4.3 Problems in Social and Emotional Developments

Visual impairment also has an impact on the social and emotional developments of these children. For example, they may fail to make and maintain eye contact with people. They may use inappropriate facial expressions and body language when interacting with people. They may lack self-confidence and social competence and may therefore have feelings of insecurity and anxiety. It is thus not unusual to find visually impaired children with little or no initiative in social interaction.

2.4.4 Difficulties in
Visual Functioning

Visual defects may affect the children's visual functioning. However, visual problems cannot be generalized. For example, some children may have poor near vision, while others may have
tunnel vision
patchy vision, or they may be susceptible to strong light and glare. But no matter what their problems are, their educational progress is invariably hampered by their visual defects. Generally speaking, visually impaired children may have difficulties in searching, scanning, and organizing visual information and in retrieving what has been dropped. They may be unable to read the blackboard, projected materials, print and diagrams of small sizes. As each child's problem is unique, strategies to cope with problems are highly individual.

Visually impaired children have to face more learning difficulties than ordinary children. With their limited experience, they normally have little or no learning skills. As there is little or no imitative
learning through vision, their learning will also be slow and their
attention span
short. They may require more time to complete a task. With limited mobility, they may encounter difficulties when participating in classroom activities, games and outdoor activities. Low self-esteem and poor social skills may also lead to emotional and behaviour problems. Visually impaired children with other additional disabilities may have even greater learning difficulties than those without.


2.5 General Principles in Teaching Visually Impaired Children

The most important principle is to monitor the children's progress regularly. Systematic planning in teaching should be emphasized. The approach should consist in understanding the learning needs of the children; planning long term and short term teaching objectives; assessing the children's
baselines; providing a favourable learning environment and adequate resources; adopting appropriate teaching approaches; carrying out evaluation and keeping record of progress.


2.6 Teaching Approaches

There are a number of teaching approaches that the teacher can adopt, for example, teaching through activities,
role play,
unit teaching,
discovery method,
programmed instruction,
behaviour modification, etc. The following suggestions may serve as reference for teaching visually impaired children:

2.6.1 Emphasis on Concrete Experience

(1) Basic Teaching Approaches

Visually impaired children cannot learn by imitation through visual experience alone. They need to do it through their other senses also, such as sense of hearing and sense of touch. Appropriate teaching aids should therefore be used to allow them to touch and learn from concrete experience. What they have learnt will thus be clearer and more accurate.

(2) Use of Verbal Instructions

Instructions and explanations given by the teacher should be clear and concise. The teacher should read out clearly everything written on the blackboard. When speaking to the children, he should first address them by their names to ensure attention. To make sure that the children understand what is taught, he should ask them questions when necessary.

(3) Management of Printed Materials and Diagrams

According to the visual condition of individual children, the teacher should choose appropriate teaching materials to meet their individual learning needs. Printed materials and diagrams may have to be adapted by using contrasting colours, tactile marks, enlarged size, increased boldness, adequate spacing, etc. In producing tactile diagrams for these children, the teacher should note the following:


choose diagrams of appropriate sizes to suit the fingertips of totally blind or severe low vision children;

(b) simplify cluttered or superimposed diagrams without compromising accuracy;

emphasize the most important areas, lines and points in tactile diagrams;

(d) avoid cluttering too much information and coding on one page, or this will confuse the children.

(4) Classroom Organization and Management


Attention should be given to classroom organization and management so as to provide optimum learning. The classroom should be big enough to allow the children safe mobility. The children should be provided with large desktops for their bulky textbooks and equipment so that they can have a comfortable work area. Since natural light is the best source of illumination, low vision children will benefit from sitting by the window or the Wyteboard.


Although better illumination often improves the perception of low vision children, direct sunlight should be avoided. Venetian blinds can be installed to address the problem. In gloomy days or other adverse illumination situations, intensive lights with background lighting of diffused fluorescent lights can be installed in the classroom especially for low vision children who use ink-print books. As far as possible, the surface of furniture or walls should best be in matt finish to avoid unnecessary glare. In order to facilitate the use of intensive lighting, audio and visual equipment, adequate electric power points should be installed safely in appropriate places.


The classroom should be equipped with adequate notice-boards for display of learning materials, timetables, schedules, educational posters, children's work, etc. both in print and in braille. Materials and equipment kept in a particular classroom or special room should be clearly labelled in large print or
in braille to give the children easy access. Should the teacher find it necessary to move the furniture in the classroom, all children should be informed beforehand.

(5) Safety Precautions in Conducting Outdoor Activities, Sports and Games

The teacher should take special safety precautions when conducting outdoor activities, sports and games. The activities should be conducted in spacious ground. Places with fixtures, objects or wall-blocks that can be of danger to the children should be avoided. Anything lying disused on the floor should be cleared so that the children will not fall over them. Children with history of
dislocated lens,
detached retina and
high myopia should not be allowed to carry heavy loads or take part in vigorous activities. Children with
albinism should not be asked to stand for too long uncovered under strong sunlight. They can wear tinted glasses to reduce the discomfort caused by the glaring sun. Children who require spectacles should wear plastic glasses.


2.6.2 Specific Teaching Strategies for Totally Blind and Severe Low Vision Children

(1) Medium of Literacy

As visually impaired children are not able to use print as a means of communication, braille has to be used instead. Before the children are ready for
braille reading, training in the development of
tactile sensitivity of the hand is important. Training in
long and short term memory to retain the impression of
configuration of symbols is helpful to the development of reading readiness. English and Chinese braille should be taught as early as the children are ready to learn them.

A good braille reader usually moves his fingers lightly along the braille line without regression. High level of concentration and comprehension is required in speed reading. The teacher should discourage reading by scrubbing movement, lip movement and subvocalization. Braille writing is usually introduced with the Brailler. Writing with a
hand frame should be introduced later when the children need to write short notes.

(2) Developing Skills in Other Modalities

Tactile Skills

Direct contact by means of touch is the only way in which totally blind and severe low vision children can learn about form and texture. Thus the way in which the hands are used for exploration is significant. The teacher should understand the importance of tactile perception in the children's development. Guided tactile manipulation and exploration with supportive language can help the children to establish concepts such as rough, smooth, hard, soft, etc.

Encouragement should be given to increase the range of investigations by using different tactile strategies such as scanning with a flat hand, manipulation with fingers and the thumb, etc. Visually impaired children need to have maximum opportunities for first-hand exploration of objects.

Auditory Skills

For children with defective vision it is important to be able to listen critically and with concentration to auditory information. The teacher may offer programmes that encourage the children to pay attention to auditory materials and provide tape-recorded materials instead of, or in addition to, printed or braille texts. The teacher can devise listening activities to reinforce what has been learnt.


2.6.3 Specific Teaching Strategies for Mild and Moderate Low Vision Children

(1) Training In Visual Efficiency

Children with
residual vision should receive training in visual efficiency. This includes figure-ground discrimination, shape constancy, perception of letters and words, visual memory, eye-hand coordination, use of visual aids, use of lighting, etc.

(2) Favourable Visual Environment

The teacher should provide a favourable visual environment in the classroom for the children. In all learning materials provided for the children, attention has to be given to quality in terms of good contrasts and appropriate print sizes and spacing. The paper used should not be glossy. There should not be too many colours on one page or this will confuse the children.

(3) Way to Help Reading

The children should be encouraged to read with book-stands so that they do not have to bend over the table for too long. Reading with page markers and reading windows will be helpful to the children, who find it difficult to focus on a word or a line of print. Lamps with variable light intensity and position can provide the children with suitable lighting for reading.

(4) Way to help Writing

Writing may be a great problem to many mild and moderate low vision children. Black felt pens or soft dark pencils can be used with bold-line paper for writing. The children can also be taught to type or use a computer for writing. Long sessions of desk work should also be avoided to prevent the children from visual fatigue.

(5) Way to Save Vision

The children should be asked to use close vision and intermediate vision at alternate intervals so that they can relax visually. Since these children are unable to see demonstrations and writing from the distance, they should be encouraged to make
proper use of optical
or technical aids in order to see clearly.


2.7 Use of Special Aids and Equipment

For the education of visually impaired children, it is necessary to use a variety of teaching aids and equipment to help them to learn. What aids and equipment to use will depend on the children's visual functioning and educational levels. Owing to rapid development in technology, the list of adaptive aids and equipment shown below is not exhaustive. However, they can be categorized into visual, tactile, auditory and computer aids and equipment.

Visual Aids and Equipment

Closed circuit television : used to enlarge images on a television screen with variable sizes, contrasts and illumination.

(2) Lighting : using lamps to provide the amount and angle of light required for maximum reading efficiency.
(3) Textbooks and instructional materials : learning materials to be presented in large print.
(4) Book-stand or raised desk-top : to bring printed materials closer to the children's eyes for better lighting and easy reading.
(5) Optical aids : spectacles, contact lens, telescopes and magnifiers, which are important low vision aids and should best be prescribed by qualified professionals.

2.7.2 Tactile Aids and Equipment

Braille books : books transcribed into braille.

Optacon : an electronic reading device which transforms ink-print characters in books with an electronic lens into vibrating shapes that can be read tactilely with a single finger.
Paperless braille writer : a braille writing and reading device which can store braille written information on audio cassette tapes, floppy disks or computer chips and can be retrieved later to be read on a braille display or in synthetic speech output, e.g. VersaBraille, Eureka/ Braillemate, etc.
(4) Slates and stylus : writing slates made either in a plastic or metal frame with openings through which braille dots are punched with a pointed stylus.

Thermoform duplicators : duplicating machines for mass-producing plastic braille pages and raised pictures for braille users.

Auditory Aids and Equipment

Print access reading systems for totally blind and severe low vision children : the Kurzweil Reading Machine, OSCAR or Arkenstone Reading Systems using computer scanning technology to convert print into synthetic speech output.


Audio tapes and recorders : useful for taking notes, recording homework, listening to assignments, etc.

(3) Talking calculators, clocks, electronic dictionaries, etc. : aids available with synthetic speech output.

2.7.4 Computer Applications

Microcomputers, operated with appropriate special software and computer adaptive devices, make it possible for visually impaired children to have equal access to electronic data like their sighted peers. Besides learning the computer as a subject in special schools, visually impaired children can use the computer to assist them in learning other academic subjects and as an aid to communication with sighted children.