Vision for Doing
Assessing Functional Vision of Learners who are Multiply Disabled
Part 1: Laying the Foundations
Chapter 1: Assessment and Functional Vision
In this chapter we cover two areas. In the first section, we present our use of the term Assessment. In the process we outline what we believe to be a different and widely acceptable basis on which to carry out assessment.
Having adopted this broad view of assessment, the second part of the chapter discusses what this assessment might be directed to: that is Functional Vision; the main theme of Vision for Doing
What is assessment?
In the 1970's Edward de Bono, among others, became famous by asking people to think of as many uses as they possibly could for objects such as a brick, or a shoelace. The more uses a person could think up, the more able that person was to think laterally, or divergently. Those who were only able to think of very few uses for a brick were deemed convergent thinkers. Readers of the many books on this subject were then able to decide for themselves whether they were lateral or divergent thinkers.
Perhaps you would like to indulge in a spot of lateral thinking? We will not ask you to imagine uses for a brick. Try instead to think of as many different uses of the term 'Assessment' before consulting table 1.1.
Table 1.1 presents information on the bases of whether the form of Assessment occurs at a society or population level (macro-level) versus at the level of the individual (the micro-level). Of course in reality there is no such hard distinction. There is much overlap. However, it shows indicate that there are good reasons for regarding assessment as being of potential benefit as well as a possible instrument of social control; witness the terrible events of the Soviet Gulags1 and, in the West, the debacle of immigration at Ellis Island, New York in the 1920's2.
One can see why it is that in some realms, it has become fashionable to knock the whole idea of assessment. Nor is it difficult to see why some people have come to reject the possibility of assessment as being a 'good thing'.
Assessment does not for us construe an evaluation of the learner; it also does not happen at any one time; and it should not leave out a contribution to understanding which areas of the learner's curriculum could be usefully explored; and how. For our purposes and as a working definition we will be interested in the use of assessment to offer practical information in order to help bring about beneficial change.
'Assessment' is a word familiar to the parents of children with special educational needs. It may well conjure up memories of long hours spent telling the familiar story of the birth and early years of life of their child and answering innumerable questions about what he or she can or cannot do. Most people cooperate willingly as it is hoped that from this process will come some means to help their child progress or to find the right school for her/his needs.
In other words, as shown in Table 1.1 at the beginning of this chapter, assessment can be a means to an end, not an end in itself. However, this may not always be clear especially when assessment procedures do not result in much practical information or help for parents or teachers. This may often seem to be the case when vision is being assessed, if the child or young person is unable to cooperate or respond verbally in the assessment situation.
If for instance glasses or magnifiers were provided as the result of an eye test, at least that would be a concrete outcome of the process. However, the outcome of even a long series of tests can be inconclusive and often difficult to understand. If the implications of the findings cannot be translated into practical guidance for day to day living, then everyone can be left with a feeling of dissatisfaction. Some of the reasons for this disappointing state of affairs include the following; you could probably add some to the list yourself:
- the person being assessed was frightened by strange surroundings or unfamiliar people;
- the person's other disabilities were not taken into account and the methods used might therefore have been inappropriate;
- people carrying out the assessment were not familiar with the child's home environment or school curriculum.
What can we learn from this? At least three things:
- a learner will respond best in familiar surroundings and with known, trusted people;
- some days the response will be better than others and there may be changes over time due to maturation, so it is important to see assessment as an ongoing process;
- it is important to use all the other information that is already available so all those who know the child should contribute, parents and professionals.
Table 1.2 presents some of the reasons for assessment going wrong. As you look at the table, think of any situations in which you have experienced such obstacles to assessment.
Assessment as counselling?
As the result of a series of national disasters, such as Piper Alpha and the Lockerbie air crash, as well as media attention in cases of child abuse, public awareness of the term 'counselling' has grown. We would like to propose that you begin to regard assessment as having many similarities to the ways in which a skilled counsellor might work. We offer the following analogy to help understand our view of good assessment.
In the realm of counselling this analogy is itself sometimes employed to give the flavour of what the counselling process is about. Imagine therefore a person looking out of a window. Your job is to help the person to see what is outside the window. How might you do this?
Figure 1.1 identifies three ways of helping the person to see what is outside the window
In Figure 1.1(a) we have the first type of help that could be offered to the person looking out of the window. This would simply be to leave them alone, otherwise you might well be interfering. But what if the person has come to you for help? They want to be helped to see more clearly out of that window.
In the process of assessment, this way of helping is represented by not conducting any form of assessment. This is an approach much favoured within the field of multiple disability; so far as vision is concerned. This was one of the reasons we carried out the work which led to this book.
You might have thought of a second type of help to offer, as seen in Figure 1.1(b). This would be to help the person by describing or relating what is out there, beyond the window. You might do this by turning the person's body in a specific direction, perhaps pointing out disctinctive landmarks, filling all of the details, and so on. In doing so, you would in effect by directing the person as to what to see. This too is not counselling. It represents one form of helping, but it is not counselling.
Nor is it like what we call assessment. There are plenty of examples in the domain of multiple disability, in which being directive is all and giving opportunity is forgotten. In fact we see this whole area as being of such importance that we devote one of our central working principles to this subject (see Chapter 4).
We hope that you would then try out an altogether different way of helping that person to see out of the window (as shown in Figure 1.1(c). You could try to share that person's frame of reference, to see out of that window but not just what they see, but how they see it. In doing so, you would be trying to understand that person's world from his or her own perspective. The previous two frames of reference are quite unlike the share perspective of this third view.
Counsellors strive very hard to take the frame of reference of the client. As far as possible, they will perceive the situations, people and events as perceived by that client. In this way, they probe for paths of change that will be meaningful to the client. In remaining the problem of the client, any change that happens stems rom within the clients. He or she discovers the right path or paths in his or her world of people and events. Those being counselled are neither left to fed for themselves, nor are they instructed as to how to solve their problems.
It is this shared perspective we are aiming for when we attempt an answer to the question of how in our own work good practice will bear fruit.
While we coud develop these issues in much greater depth, we wish in this book merely to get across that there are salient differences in the style with which we think assessment should be carried out and why it is a good thing to do. In fact we view it as an activity that is indispensable. Assessment is not therefore one activity to be done at one time of the day. Instead it should be present in everything we do. For it is simply the means of trying to comprehend better how a learner with multiple disability comes to understand his or her own world. Through that improved understanding we come to develop methods for offering to the child other aspects of her world.
Often those who work with learners who have multiple impairment believe that assessment materials offer no gain to them. They feel that what is important is to be able to 'get to know the person'. In many ways this is true. However, if we were to agree that this is all there is to assessment, then there would be little point to producing this book. It is no bad thing to retain in a scheme of assessment the richness that is contributed by 'getting to know the child (or young person)'. At the same time, a book like this can help to frame questions, to suggest a few activities. After reading the book, it will still be you who will know the learner's ways best of all. The longer you spend trying to understand the learner's frame of reference on the world, and the more questions you pose, the more aware you will become of that specific learner's motivation, interests, and awareness of people, places, objects and events in the world.
The analogy of counselling takes us some of the way, identifying the general nature of the process involved. Nevertheless we need to be more specific as to just what is expected of the process of assessment. Counselling would have a pretty flimsy basis if it depended solely on our imaginary window on the world. So too would assessment.
The cycle of assessment
Assessment does not occur just at one level. Instead there are many different levels at which assesment could be carried out. Also rather than occurring at distinctly different levels, these levels tend to interact. So a visit to the doctor or a biochemical investigation has an effect on the child, parents and thereby possibly on a teacher.
Structuring out approach enables us to go beyond guesswork. By observice a learner's responses we establish a base-line or starting point. From this starting point we can plan the learning experiences and strategies accordingly. We can also review, or re-assess and record any subsequent changes in functioning.
We would like to propose that the process of assessment be considered in terms of a cyclical process. Within each step, you attempt to understand the world from the point of the learner. The cycle of assessment can then be thought of in terms of four broad steps or stages. Figure 1.2 depicts each of the four stages.
Usually you would begin by identiyfing the Personal Aspects of a learner. Having done so, it should be useful to formulate these in terms of the different Settings or contexts experienced by the learner. Without some knowledge of the Resources at your disposal, it could be difficult to set specific Learning Objectives, or new activities. In the next Chapter we will be returning to the Cycle of Assessment, and considering each of these steps in greater detail. First we reflect on Vision for Doing, our topic in the second half of this chapter.
By Vision for Doing we mean any remaining sight, no matter how little, by means of which the learner can add to his experience, enjoyment and learning about the world. This includes sight which is so poor as to enable the person to tell only light from darkness.
Many parents, educators and carers have been misled by the description "This child is blind". They have taken it to mean that the child lives in a world of darkness. There is then no point in trying to make the learning environment visually interesting, for it will not be seen. This belief is somewhat misleading. Very few people who are described medically as blind are totally without vision.
Table 1.3 lists a few types of blindness. Some are associated with poverty and lack of public health measures; others are associated with industrialised countries. If you are interested in finding out more about these conditions, refer to the Glossary section at the end of the book.
It is true to say that it is the legal definition of 'blindness' which determines a person's status; rights to certain benefits; the possibility of being labelled; and rights to specialised equipment at discounted rates. The legal definition of blindness varies from country to country. In fact in 1966 the World Health Organisation documented the then known definitions. There were 65 different definitions! In the USA alone there were 16 different definitions for blindness (Goldstein, 1980).
Only about 5% of the total population of people who are considered blind or visually impaired are in fact totally blind. Any children or young people stated as being blind or visually impaired whom you meet are therefore likely to have some vision available. It is for this reason that it is so useful to try to determine how much a learner can see, the best position in which they see and the optimum location for presenting materials and activities. For instance, for registration purposes a definition of blindness may be that the person does not have enough vision to do a job for which sight is essential. This in no way rules out the presence of useful sight.
What we mean by Vision for Doing is just this sort of functional description. Its investigation is concerned with the objects, events and places in the world. In this book we do not devote much space to dealing with the effects of total blindness. The book is after all a schedule for working with learners who may have some residual vision - useful remaining sight. The implications drawn are for the most part directed to those areas of curricular development for learners who have some, albeit very limited, vision.
Our visual world
The first task of vision is to make us aware of our environment. Sight allows babies to develop precise reaching and to recognise and interact with important care givers. It helps us in walking and running both indoors and out. Through this sense we become increasingly aware of our surroundings. Objects can begin to take on new meanings.
It tells us how objects are related to each other in space - whether in front or behind; moving or stationary; near or far; above or below. Vision also provides us with information usually associated in our minds with other senses. Not only touch tells us whether an object is rough or smooth: vision also detects textural changes. Vision is important for mobility giving us guidance indoors and outdoors, and informing us whether we are moving in relation to our environment, or the environment in relation to ourselves.
Vision for detail
We use our sight for detailed information. This kind of vision lets us see the finer grain of objects, pictures, people, letters and symbols. As we need to identify symbols in order to be able to read and write normally, it follows that any impairment of this 'sight for detail' will affect abilities in reading and writing. You will already be familiar with testing or assessment of this detailed vision. This testing gives a measure of visual acuity.
We learn to interpret pictures, do jigsaw puzzles, look at television and to read. Our visual world is complex, varying along several dimensions, eg; figures/ground; surface/edge; movement of self/movement of objects in the world; hard/soft; near/far; big/small; changes in perspective; changes in colour.
Some specific functions
In order to detect this complexity in our visual world, our visual system provides information on a large part of one's surroundings (field of vision); distinguishes details (visual acuity); detects the difference between relative brightness of different surfaces (contrast sensitivity); contributes to judging distance (binocular co-ordination); allows us to see in poor light (darkness adaptation); and to (quickly) accustomise to strong light (light adaptation); helps us distinguish between different shades of colour (colour vision); (reprinted with author's permission from 'How Well Does a Child See? Eva Lindstedt).
Unfortunately impairment may occur to any one or more of these visual abilities. These impairments may for the otherwise able-bodied child not only produce a distorted sense of visual surroundings, but can also switch off any interest in these surroundings. For those with multiple impairment, the job of seeing becomes even harder. The fun can be completely removed from the activity of seeing. The child with learning difficulties will be uninterested in shape sorting or matching tasks if, because of poor sight, all shapes beyond a certain distance appear as circles. The child with a hearing impairment will have less to communicate if she cannot take note of important visual cues in communication - missing as she does the pointing, facial expressions or eye movements of potential partners in communication. For the learner with multiple disability those additional disabilities can make the impairment of sight present disproportionately greater difficulties.
As we mentioned in the Introduction to this book, the authors investigated established practice in the visual assessment of learners who were multiply disabled. Our findings included the discovery of a range of assessment techniques used, along with the frequency of their usage. These are presented in Table 1.4.
For most of the children who were involved in our study, these techniques would furnish little information that would be of relevance to curricular planning. In fact many of them could, if used, lead to highly ambiguous results. To understand why this is so for each and every technique would be beyond the scope of this book. However, to illustrate we will use two examples drawn from Table 1.4. The first example deals with Electrical Testing. The second example is concerned with a relatively new clinical procedure, Fixation Preference.
How it works
You may have come across the use of electrical testing. If so you may know it as VER or VEP (Visually Evoked Response or Potential); ERG (Electroretinogram); or EOG (Electro Oculo Graph). Each is used for a different purpose. Ophthalomologists have made frequent use of this form of testing (as there is more than one form of electrical testing for vision, it is more accurate to say these forms, however as we are only touching on this subject, we will use the simplified singular term for convenience). To carry out the test, electrodes are placed in one of a variety of combinations of sites around the child's head and eyes. The procedure is not painful. Various stimuli are then presented usually on a TV monitor and, so the theory goes, if the eyes and/or brain are working, an electrical potential should be recorded.
Electrical testing can be an extremely useful procedure, resulting in early diagnosis of Retinitis Pigmentosa or Cortical Blindness (see Glossary section at the end for further explanation of these terms), among other benefits. It can also be misleading. There have been many cases of learners with useful vision being recorded as totally blind. Vice-versa, there have been cases of electrical potentials being recorded, but the child being functionally blind. Both the authors have seen many cases of the former, and a couple of the latter. Why should this be so? Surely such a measure - using sophisticated technology - should be more objective? Unfortunately - and not for the first time in modern bio-medicine - one cannot draw a clear comparison between the technological sophistication of a test and its validity or accuracy.
In using recorded potentials, comparison is made with an average. This is then used to provide an arbitrary cut-off point, below which blindness is designated. This should sound familiar to the reader. In essence this is the same situation as with the definition of blindness. We indicated that a relatively arbitrary cut-off point was used to define legal blindness. The same is true for electrical testing.
Many other medical tests demonstrate similar problems. You may well be familiar with these from the field of medicine. For instance, the diagnosis of diabetes is based on an average blood sugar level. But there can be variation from this average, without the person showing any clinical sign or symptom of diabetes. Definitions of normal versus abnormal are long way from being as clear-cut as many would like to have us believe. This is one of the central problems in the area of medical screening (or more accurately called surveillance).
You may of course argue that it surely does not matter if a test happens to return false negatives or false positives. Provided the child is seen to have visual functioning, then surely everything should proceed as appropriate. But there at least two reasons for needing more accurate information on visual functioning.
One of the findings in the study which led to this book being written was that electrical testing was frequently used as a test of second resort (see Table 1.4. below). Where the most frequently used test was found not to be helpful, then electrical testing tended to be the next technique to be tried. Apparently, it was felt that electrical testing was regarded as more accurate than anything else. The only reason for it not to have been used in every case was one of cost. In other words, the inherent problems of electrical testing were not being recognised.
The second problem with electrical testing lies in the fact that it is often seen as being most useful when applied to babies and to older children who have multiple disability. When told that their baby is blind, parents often feel that there is little point in trying to encourage the use of vision. After all, what is the point in stimulating something that is not there? When applied to the learner who is multiply disabled, this problem is accentuated. As will be seen in later chapters, this is not always a valid assumption to make. Where even very limited vision is found to exist, there are many techniques to harness use of that vision to increase the availability of the learner's potential world.
This is our second example of a tool used to assess the vision of individuals who are multiply disabled (see Table 1.4 above). Use of the technique of Fixation Preference (or FP as we shall call it) has burgeoned over the past 10 to 15 years, providing a fertile source of research for those interested in the development of vision in babies. What began as a research tool, for psychologists studying the events in which young babies were interested, has moved on to take its place in the clinics of many ophthalmologists who routinely test the vision of children. Its use with those who are multiply disabled is also increasing.
How it works
FP is a measure of the ability of the eyes to resolve detail. It does not require language abilities, nor ability to point, nor that the testee be able to follow instructions - hence its value to those wishing to test the sight of infants and people with multiple disability.
Figure 1.3. shows a rough approximation to the stimuli presented to the person being tested. There is a striped target stimulus like a set of gratings, and a second blank stimulus. Usually, the target is presented as a series of vertical black stripes, the narrower and closer together the stripes, the greater the acuity required to resolve them apart. Equidistant from the midline at the same height, same size and shape as the target stimulus, a second target is presented. This target is blank. (Actually it is not quite blank. It has an overall grey value that is identical to the average greyness of the black/white striped gratings of the first target.) This comparison is needed so as to be more certain that, if the child looks at (fixates) the first target, it is due to ability to resolve detail and not to detecting brightness differences. By averaging the black/white of Target 1, with the same average grey value of Target 2, the tester can be more certain she is checking acuity. The pattern of the target stimulus is preferred to that of the 'blank' stimulus.
As the width of the gratings gets narrower, the two stimuli become indistinguishable. Those with poorer vision will find it less easy to distinguish the gratings than those with good sight. By grading the width of the stripes or gratings, this can be used as a tool in place of the eye chart which will be familiar to most readers. These gradings are then represented on individual large cards (often known as Teller cards)3.
As it is difficult for manufacturers to achieve just the right average values of luminance, these are fairly expensive as tools for assessment. Nonetheless they have become widely used instruments in infancy research - so much so that more than one respected researcher has questioned whether 'infant vision is disappearing down the gratings'.
Nowadays, FP mostly makes use of Teller cards. These are very portable, can be positioned near to the child and at any angle, thereby coping with the unusual positions often taken up by children who are multiply disabled.
What goes wrong?
It is only in more recent times that fixation preference as a technique has come into greater use within clinical practice. Nevertheless, consideration needs to be given to some of the issues raised by its use. First, in common with other measures of visual acuity, it shares a problem of interpretation. One of the principal reasons behind us being driven to offer assessment of functional vision was, as we have said, a lack of information on implications to be drawn from standard measures of acuity. FP suffers from the same problem. If we find that a learner who is multiply disabled looks at gratings which are equivalent to a visual acuity of 3/60, then we still have to work out what to do with that child. If we also have direct behavioural measures we are a step forward in setting learning objectives4.
A story may illustrate a second type of problem. One of the authors was visiting a centre of excellence in Scandinavia, where they made use of FP. A girl of 14 years who was severely multiply disabled was being tested, accompanied by the specialist teacher for visually impaired and the girl's mother. Two very experienced FP testers were in attendance (a reliability check on the test can then be made on the spot). After repeated Teller card presentations, the testers gave up, saying that they thought the girl might be able to see light, but no more.
Meanwhile the girl's teacher and the author, both of whom were out of sight of the girl, exchanged glances. We had both realised immediately that the girl was attempting to communicate through eye pointing. To do so, she had to avoid both grating and grey square. It transpired that the girl had a fairly complex eye coding system established. The moral of this story is that there is no point in testing the sight of multiply disabled people by itself. What is interesting is to test Vision for Doing.
Aside from these difficulties in use of FP, there are one or two practical problems. If there is muscle imbalance or squint present, it may be hard to decide to which side a child is fixating. Nevertheless, FP may often be a very useful technique, one of the easiest to carry out, though, as we have seen, not without difficulties in interpretation.
In this chapter we covered issues which deal with assessment, allowing us to move on to an analysis of how this relates to functional vision or Vision for Doing'. We discovered that there are grounds for those who are suspicious of the term 'assessment', it having had a rather chequered history.
An understanding which began by taking as a metaphor the process of counselling helped to demonstrate that there was a real contribution to be made by 'assessment'. We elaborated on this by introducing the notion of this process of assessment as being in the nature of a cyclical set of stages or steps. Not surprisingly this is a topic to which we will return, as the subject matter of the next chapter.
In the second half of this chapter, we began to look at the question "What are we to assess?". We found that vision allows us to perform many functions in the world. For the learner who is multiply disabled, visual impairment can accentuate greatly the difficulties of finding out about that world. When examined, the nature of standard test instruments were found wanting when applied to the learner with multiple disabilities.
In the next chapter, we take up our metaphor drawn from counselling. This time the frame of reference we try to take happens to be your own. We offer what we think will be ways by which you probably already try to understand your learner with multiple disability.