All children know that they are normal. Our frame of reference for normality is ourselves, and not the rest of the population. Teachers also know that they are normal and set material on the basis of their own visual abilities. But when the "normal" child with visual impairment meets the teacher with "normal" vision, problems can arise.
Teacher: "Look at the tiger in this picture." Child (thinks): "What tiger?" (The detail is too small to see the tiger.) Teacher thinks: "Stupid child." Child thinks: "Stupid teacher." They are ships passing in the night.
This example shows why integration into mainstream schooling - although an excellent concept for many children - can present difficulties for pupils with special needs. All too often, the environment and conditions are not adequately considered from the child's point of view. In the case of the child with visual impairment, (of whom there are about 2,000 in Scotland alone, most in mainstream education), there is a wide range of potential problems that need to be sorted out.
Visual acuity is a measure of how clearly we can see. The term 66 indicates normal clarity of vision, while for example the term 624 means that the clarity of vision is one quarter of normal clarity and either the child needs to be four times closer or the information needs to be four times bigger. Or a combination is required for detail to be seen.
A pen with a nib size that is four times thicker than normal enables the child to write with larger letters and to see their own work with the same clarity as their contemporaries. The measured effects of visual blurring are shown in the above pictures. (Sensitivity to contrast is another aspect of vision that is commonly impaired and this concept is also illustrated.)
The visual field is an assessment of the area over which we can see. If there is damage to the brain at the back on one side, the child cannot see on the opposite side with both eyes. Children with this problem benefit from sitting with the teacher off centre to the sighted side.
A child with albinism (a congenital lack of pigment that produces white or translucent skin, white or colourless hair and eyes with lightly coloured irises, and to and fro movement of the eyes) can be affected by glare and bright lighting because too much light gets into the eye.
On the other hand, a child who is born with night blindness needs good lighting throughout the building. It is frightening to have to walk through darkened areas, because the child can't see and they can take a long time to get used to changes in lighting.
If there is damage to the brain affecting how a child sees, the commonest problem is difficulty handling complicated visual scenes. Difficulties include being unable to see something pointed out in the distance (the further away things are the more there is to see); inability to find mum in a group of mums, or a friend in the playground; inability to find an item of clothing in a pile of clothes and inability to find a toy in a toy box or on a patterned background.
Sorting possessions so that searching has only to be in one dimension and not three makes a considerable difference. Such children have great difficulties copying and expecting them to do so is similar to expecting children in wheelchairs to cope with stairs.
We use vision to access information (both near and far), to communicate and to guide all our movements. Text needs to be of a size that affords maximum speed of access to the information. The smallest detail in pictures needs to be visible, for example the eyes of a teddy bear, otherwise the child "knows" that teddy bears often don't have eyes. Text on the whiteboard needs to be the correct size.
For communication, the facial expression recognition distance needs to be known. This is easy to find out, simply by asking what one's expression means at progressively greater distances. Children who cannot recognise faces or expressions due to poor vision need to be taught with radio, not TV language - in other words, language that makes no reference to the visual surroundings and does not assume the child can see facial expression or body language. (Close your eyes and listen to the TV. Does it make sense?) Those who have such limited vision that they cannot guide their movements need to use tactile strategies to get about.
All the children in the class need to understand how to behave and interact with a visually-impaired child in order to break down barriers and misconceptions. Buddy systems can help a lot in many cases.
Ideally, no child should be educationally or socially disadvantaged on account of poor vision, but mainstream integration is letting down many children whose difficulties are insufficiently understood. They can spend extra time at school and at home working at the limits of their capabilities and it isn't surprising that they can behave badly at times.
Ensuring that work is well within the child's ability to see it is essential, and all teachers should be aware of the peripatetic educational service that is potentially available for all visually-impaired children throughout the UK, and how to contact this service locally.
Matching the environment and imagery to the special child's needs so that all educational material is easily seen and does not hamper their classmates is essential. This is attained by accurately imagining the world as the child sees it, and acting accordingly.
Gordon N. Dutton is consultant ophthalmologist at the Royal Hospital for Sick Children in Yorkhill, Glasgow, and professor of vision science at Glasgow Caledonian University.