2. Introduction to Vision Loss

SUSAN BASHINSKI:

SLIDE 1
Hello. My name is Susan Bashinski, and I've been invited by the staff of the Kansas 
Deaf-Blind Project to visit with you today about a basic introduction to vision loss. 
So if you're ready, here we go.

SLIDE 2
Vision impairments or vision losses present themselves in a number of very different ways. 
What you see on the screen now is a listing of the five primary categories or types of vision loss. 
Later in this presentation we'll examine each of these in much more detail. But for now, as a 
preview of what's to come, we'll name each of the categories briefly with a very short definition. 


The first category, acuity loss, represents the largest number of cases of vision impairment experienced by kids. 
This is the largest category of the types of vision impairment that refers to how well a person sees. 
The second category, field loss, or visual field loss, refers to the range in space through which a person 
does or does not see. 

The third category, contrast sensitivity. This one is a little bit different. It has 
to do with lighting and how well or how poorly a person can see differences in size in objects that are not 
outlined clearly or that don't stand out against the background. 

The fourth category is processing problems. 
Typically, this is referred to as CVI-- the initials on the screen-- which stand for cortical vision impairment. 
This fourth category represents a type of vision loss in which the challenge-- the difficulty-- is not in the 
eye or the optic nerve itself. Cortical vision impairment, or CVI, is a problem that occurs in the cortex of 
the brain-- how the brain actually handles or quote, "processes" the visual information it receives. 


The fifth category of a particular type of vision loss is ocular motor problems. Problems of this type have 
to do with the pairs of muscles in the eyes. And these have to do with how a child tracks or stabilizes gaze, 
or can shift his or her gaze from one object to another. 

The final category-- combination problems. 
That's exactly what you would infer it means from the name. Any of these five types of vision loss we've mentioned 
may occur in combination with one another. 

SLIDE 3
Let's begin now with a brief examination of the first primary category of vision loss, visual acuity. 
The definition is presented on your screen. Visual acuity measures the ability of the eyes to focus sharply on an image. 


In addition to this actual definition, one very important aspect to remember is that any measure of visual acuity 
represents an individual's central, not peripheral, visual acuity. What this means is the measure, the numbers that 
you would receive from an optometrist or an ophthalmologist, that describe how well a person sees refers to how well 
she sees when her shoulders are squared, her head is straightforward, eyes are facing straightforward, and that is the 
acuity measure-- central, straight ahead, in front of the face. The visual acuity measure does not refer to how well that 
individual sees out of the, quote, "corners of her eyes," to the right, or to the left sides. 

SLIDE 4
Having defined visual acuity, we now want to define a visual acuity loss. Acuity loss refers to a decreased ability of 
the eyes to distinguish object details and shape. Technically, we could say it's a decreased ability to distinguish details 
of persons, places, things, signs. It's not only objects. It could be facial gestures, the letters on a sign, anything a 
person might see, remembering acuity refers to how well a person sees, so acuity loss refers to a diminishment in this ability. 
On the next slides, we'll examine the various levels or degrees of visual acuity loss.

SLIDE 5
As we discuss acuity loss today, we will examine four primary categories, educational terminologies, that teachers, 
teachers of the visually impaired, other professionals, will use to describe how a learner's vision functions. 

We'll begin with 
the most significant type of loss, which is on your slide, referred to as totally blind. The percentage of children and young 
adults with this type of loss is very, very small. I guess I shouldn't say this type of loss. I should say with this degree of 
loss is very, very small. A learner who is totally blind does not perceive even the differences between light and dark. 
Again, a very small percentage of the population of learners with vision loss are totally blind. 

A second larger category-- still 
a very significant degree of acuity loss-- is a learner who is described as having light perception only. 
A learner with this degree of acuity loss lacks functional vision. What that means is she cannot use her vision to read, 
to discriminate objects, people in her environment. She requires tactile means for mobility, for communication. 
But this particular learner does perceive light. This particular learner is able to discriminate between light and dark, 
classic characteristic behavior of learners who have light perception only. If the learner is in a school building, 
in a hallway, then goes outside onto the playground on a super bright, sunny day, very often the minute the learner 
goes from the hallway to the playground, she looks up because she senses the sunlight. And the sun is bright, and it 
catches her attention. And she notices that. 

Some children and young adults will gravitate to very, very bright, 
sunny spaces in the house. Sometimes little children will lie on the floor next to a window where the sunshine is 
just pouring in, because they sense that brightness. Sometimes that is associated with self-stimulatory behavior, 
because the learner can produce amazing shadows by moving her hands or other objects in front of that super bright sunlight. 

SLIDE 6
The next category is a learner who would be described as having legal blindness. On your slide, you see a 
definition of legally blind. This definition has several very important parts. We'll talk about it in three parts. 
One sort of jumps into the next category of loss. 

When we talk about legal blindness, we're referring to a visual acuity of 
20 over 200. This is in the Snellen notation-- we'll talk about that in a minute-- or less. 20 over 200 or less in the better eye, 
with the best possible correction that can be achieved for that learner. 

And then the second criterion is that a learner might 
be declared legally blind if he sees through a visual field that is no greater than 20 degrees. I'd ask you to set that 
very final part of this definition aside for a few minutes. We need to dissect the other parts of the definition. 


So what does it mean when we say 20 over 200 in Snellen notation? Well, the Snellen chart, each of you has experienced 
at some point in time. When you go in your eye doctor's office, optometrist, ophthalmologist is the chart with the big E 
on the top. That's the Snellen chart. 

And in the Snellen notation, a visual acuity of 20 over 200 translates to mean. 
A learner with this level of loss must be within a distance of 20 feet of an object, a person, a sign, whatever-- within 
a distance of 20 feet in order to be able to clearly discern what a person who has normal or typical vision can see clearly 
at a distance of 200 feet. So the learner who is legally blind must be 10 times closer than a person who has quote 20/20 vision. 


The second aspect of this definition of legal blindness that's a really tricky one, and it tricks up many of us, is to say 
that the visual acuity must be 20 over 200 or less in either the learner's right eye or left eye, whichever one is better, 
whichever eye-- right or left-- has the better vision with the best possible correction. So what this means I've heard people 
joke. 

Maybe you've joked as well and said, oh, man. I take off my glasses, and I'm just blind. I just cannot see anything. 
Well, maybe that would be true, except when you put your glasses back on, or you put your contact lenses in your eyes, 
back on the old Snellen chart, you could see at a level of 20/20 vision. 

So with best possible correction, you do not qualify 
for this label. You do not need to be within 20 feet of something that someone else can see at a distance of 200 feet because 
you have correction on your eyes. This label of legal blindness only applies to those children and young adults, 
who once they have glasses, if a optometrist, ophthalmologist is able to prescribe glasses. 

Once they have those glasses, 
they still cannot see any better than 20 over 200, or they still cannot see any better than what requires them to be within 
a distance of 20 feet to see what you can see at 200 feet. So it is this measure of distance or visual acuity, as well as in 
the learner's better eye, as well as in the better eye with the best possible correction that science can afford, and money 
can buy. So it's a three-pronged criteria, and it's very complicated. 

And the final aspect of legal blindness, we're sort of 
going to leave hanging out here for a few minutes, and we'll talk about it under the category of field loss. Is if learner 
does not see through an arc or through a space that is greater than 20 degrees. That is a second way a learner might qualify 
for the definition of legal blindness. And we will come back to that. 

SLIDE 7
Before we examine field loss per se, I would like to continue-- as this slide shows you-- with our discussion of 
visual acuity or acuity loss. The final category we need to examine today is the category of partial sightedness or a learner 
who has partial sight. Also, in the literature, currently referred to as a learner who has low vision. 

The criterion for this 
label of acuity loss is the learner must have a visual acuity no better than 20 over 70, but between a measured acuity of 
20 over 70 to 20 over 200. 

Let's examine that. Let's take that apart and talk about what each of those pieces mean. 

The upper 
limit-- if you will-- of 20 over 70 means that to qualify, this learner must be at a distance of 20 feet to see what an 
individual who has normal or typical vision can see at a distance of 70 feet away. Again, with the best possible correction 
in the better eye-- that just carries through the whole discussion of visual loss. 

The other end of the range of visual acuity 
loss for partial sightedness is that measure of 20 over 200-- hopefully, that sounds familiar to you. The reason the range 
for partial sightedness runs from 20 over 70 to 20 over 200 is that if a learner's vision is no better than 20 over 200 with 
the best possible correction in his better eye, then that learner qualifies as being legally blind, or as having legal blindness. 
So that's the bottom limit, if you will. The upper limit is 20 over 70. 

A learner who would qualify as only seeing with best 
possible correction 20 over 50, for example, that that learner would need to be at a distance of 20 feet to see what a typical 
seeing person can perceive at 50 feet. That learner would not qualify as having partial sightedness or as having low vision. 


In the literature, you'll see low vision referred to as saying, there's a severe visual impairment after best possible 
correction, but with increased visual functioning through the use of optical aids. Non-optical aids. Different types of 
magnifiers. Different types of learning media. Different types of environmental modifications, particularly, having to do 
with lighting, with controlling glare in the learning environment, in the home environment-- we'll talk about those things. 


These learners who qualify as having partial sightedness or low vision are children and young adults who may learn to read print. 
They are the learners who have functional vision and can learn to navigate in their environments, to read materials, 
to process educational materials through their vision, as opposed to only through [INAUDIBLE] means. 

SLIDE 8
The second category of vision loss we'll examine today is the loss of visual field. On your slide now, you see a 
definition. That field loss involves the reduction of space that is visible to the eyes when the eyes are fixated straight ahead. 


I really cannot overestimate the importance of this last part of this definition. In order to understand what a learner's 
visual field is or what a learner's visual field loss is, she needs to be sitting or standing or lying down with her head 
squared away, looking straight ahead, with her eyes pointed straight ahead of her body. If we could say that her eyes are 
in a 90-degree angle with her trunk and shoulders, that's what we're talking about. That sounds like an odd way to describe it. 
But having the head in midline as close as it can be with the face and the eyes pointed straight ahead is critical to getting 
a measure of visual field or visual field loss. 

Before we continue, let me remind you, please, of the last element of the 
definition of legal blindness. We said that one way a learner might qualify for the label of legally blind is if he has a 
visual field no greater than 20 degrees. This is a very small arc through which that learner sees. If he's looking straight 
ahead, the distance around his body-- if you start at a point straight ahead of his nose and go all the way around his body 
in a complete circle, a circle has 360 degrees in it. 

And we're saying that to have-- to be eligible for a visual field loss, 
that learner can only see through 20 of those 360 degrees of that circle. I hope you're thinking, wow, that's a really small 
area, that's a really small arc, because that is absolutely true. If the learner's visual field is no greater than 20 degrees, 
he may qualify for a definition of legally blind on that basis alone. 

SLIDE 9
This next slide lists four different types of field loss. These are the most common kinds that you will see referred to, 
not only in the professional literature, but in a learner's case reports, in a learner's cumulative files. I would hope these 
words would be triggers for which you might look as you refer-- pardon me-- as you are reviewing information provided by that 
learner's vision care professional. The term central, peripheral, upper/lower or single quadrant are types of terminologies 
used to describe field loss. So let's examine them one at a time from top to bottom. 

In a central visual field loss, it means 
the learner is not able to see people, things, objects, the environment straight ahead of her in front of her body when she 
is facing forward. It's as if there's a big black, or gray, or fuzzy circle of some size that is right in front of her face 
and she cannot see straight ahead of her. She may be able to see out to the sides or way up above the circle that is 
undecipherable or way down below the circle that is undecipherable. 

But with her head held still, she can't see straight ahead 
of her. And that is referred to as a central field loss. We don't have dimensions. We don't have measures of degrees or size 
of that loss. I don't think that is that central for the discussion we're having today. But if the learner cannot see straight 
ahead of her, that's a central visual field loss. 

The second type of loss is a peripheral field loss. And it is this type of 
loss that qualifies a learner for legal blindness-- for classification as legally blind if the peripheral loss is severe or 
sufficiently significant, it's of a large enough magnitude. When we say the loss is peripheral, it's like the inverse of a 
central loss. 

When a learner's field loss is peripheral, he might see very well straight ahead of her face-- straight ahead 
of his face when he's looking forward with his head squared away, shoulders squared away. But out to the sides, there may be 
nothing or it may be totally gray and fuzzy. It might be black. It just depends on the learner's type of loss. 

I would call 
upon you to think of the times when you have had your own vision checked and possibly your vision professional has you look 
straight ahead and they start to move an orange ball on a metal wire in from your side and they say tell me when you see the 
orange ball. What they are doing at that point in time is testing you for your peripheral visual field. And depending on how 
much or how little of your visual field is lost to the side, you still might be described as having a peripheral feel loss. 
Let's talk about the last two on our list together for just a moment. Think back to mathematics. Some of us might not want to 
think back to mathematics, but let's do that for just a moment. And you can, I hope, conjure up in your mind a picture of 
some type of a graph where you have an x-axis going from left to right and a y-axis going up and down so that you have this 
graph paper or this graph divided into four quadrants or four squares, two at the top and two at the bottom. 

So if you think 
with me, if we're talking about an upper field loss, it would mean that those two squares up above the x-axis, or the entire 
upper half of the learner's visual field when he is looking straight ahead, not cocking its head back, not dropping his chin 
down to his chest, head squared away looking straight ahead-- the upper half of the visual field might be lost to that 
particular learner. That is an upper visual field loss. 

Conversely, in some learners, you'll see exactly the opposite. 
And the lower two squares or the lower half of that area might be lost to that learner. Again, it's important to remember 
it's when the learner's shoulders are squared away, head straight ahead, neck not extended with the head thrown way back or 
head dropped to the chin, looking straight ahead when the lower half is not available to the learner because it's black, 
because it's so grayed out, because it's so fuzzy. When the other parts of the visual field are clear, that refers to a lower 
visual field loss. 

It might be worthwhile for just a moment to say it is because of these types of losses you might, 
at some point in time, observe a learner with whom you work or observe your own child, if you're a parent, cocking her head 
back really far to try to get a clearer picture of something or really dropping his head down so that his chin is practically 
resting on his chest to try to look at something that you're holding at head level. And if you see a learner doing these 
rather atypical things with head position, it could honestly be indicative of that learner having a field loss and his trying 
to get his eyes in a position to compensate for the part of the visual field that is not clear. So you want to watch for those 
types of things. 

The final category of visual field was is what I called on your side a single quadrant. Again if you would 
go back with me to the mathematical graph x-axis, horizontally left to right, y-axis dropping down in the middle top to bottom. 
And if we numbered those squares one two three four, it might be for any particular learner that one of those four squares might 
be totally unavailable visually, might be black, might be super gray, might be fuzzy, whatever, somehow or another one of those 
squares is not visually available to the learner who might be able to see clearly in the other three. It might be any one of them. 


This is another one of those times when a teacher, a parent might observe that learner positioning her body in awkward or 
unusual ways, jockeying her head around in unusual ways to try to get her eyes to see in the other three quadrants where vision is 
clear. If you observe those kind of behaviors, you do want to talk to a vision professional to get this checked out. 

SLIDE 10
The next type of vision loss we want to discuss today is contrast sensitivity. As defined on the slide you see now, contrast 
sensitivity refers to a learner's ability to detect objects, people, aspects of the environment at low contrast. 

SLIDE 11
Essential to a discussion of contrast sensitivity is the element of lighting. So that as we review this next slide where we say, 
oh, a learner's contrast sensitivity is affected by glare associated with lighting, is affected by the brightness of the lighting, 
or the hue of the lighting. It's affected by the size of the visual stimuli, because in different lighting conditions, size , 
matters and so on and so forth. 

So even though as we develop each of these aspects of contrast sensitivity, I might not continue 
to say of the lighting, of the light. I ask that you please keep saying that to yourself, because lighting provides what we need 
for us to be able to have the contrast in our environment, in the stimuli in our environment, so that we're able to discriminate 
and differentiate objects, people, details-- any aspects of our environment. Lighting provides the contrast we need. 

There is a 
saying for which I cannot take credit. I've heard it used by a number of professionals in the field of vision, that contrast is our 
friend, and glare is our enemy. You might be laughing a little bit. When I first heard that, I laughed about it. But it's one of 
the mantras that I use all the time. 

When I'm teaching, I use this with my students, and I use it for myself to try to remember. 
Contrast is our friend, glare is our enemy. And that's the first item on the list of aspects of contrast sensitivity. 

Certainly, 
contrast is affected by glare. In very glary conditions with all of us, even who are not challenged by visual problems, glare becomes 
a real difficult thing. If you have an iPhone, if you have an iPad, if you take your computer, a laptop computer, out in the sunshine, 
oh my goodness. The glare of the sunshine makes it really hard to see on those particular devices. 

If someone is trying to show 
you photographs that they've taken on a family vacation, and you are sitting beside them, and the photographs are coming up on a 
laptop computer. And then you see yourself reach out to adjust the screen forward or backward-- oh, because of the glare of the 
lights in the dining room where you're sitting. Glare can interfere so very significantly with what we are or are not able to process 
visually. We need to always be conscious of glare. 

A second aspect of contrast sensitivity is the brightness or the hue of the lighting. 
This is a second aspect that cannot be overestimated in importance. I think there is a myth in the field of education that for a 
learner who experiences problems with his or her vision, we need to provide more light, stronger light, brighter light. The whole 
idea of more is better. And that is not generally true. 

Yes, it is a fact that for some learners with some types of visual loss-- 
visual acuity loss, visual field loss, processing problems that we're going to be talking about in a few minutes. For some learners, 
brighter light, more light, is better. But for other learners, the opposite is true. 

For some learners with some types of visual 
problems, lower lighting, dimmer lighting-- I'm not saying super dim, no light at all. We can't see in the dark. But lesser lighting 
that is not so bright and possibly not so glary might be preferred. 

With some learners, they might perform better with what we 
call targeted lighting. This is the notion of something like a gooseneck lamp. You have an old desk lamp, or a pole lamp, or a 
clip-on lamp that has a bendable, pliable neck or a stem on it so that you can fold it over and target it just above the paper, 
just above the objects, just above the puzzle, just above whatever materials the learner is working with at the time. So that brighter 
light, or that special, additional light, is targeted right on the learner's materials. Sometimes targeted lighting can help with 
contrast for a learner. 

The third element on our list about contrast sensitivity is a notion of size. I think we all have some 
experience with this. As we get older, the size of the letters we need to see to read in a book certainly gets larger, doesn't it? 
And it's the same concept that applies to thinking about learners with vision loss. 

For those learners who do have functional vision, 
they might need a font size of 28 or 36 or 42 to be able to process print. For learners who have low vision, who are not described 
accurately as having partial sight, we might be able to process 12-point font, 14-point font. But for other learners, the size needs 
to increase. 

What we want to be careful about when we consider the size of visual stimuli-- it's important that our judgment, 
that our sensitivity to this, not be limited to print. I started with print as the first example because I think it is the most 
obvious example to which we as readers can relate. 

But the size of whatever materials that are provided to the learner-- if it's 
plastic shapes, if it's wooden numerals, if it's different types of items or objects to learner is supposed to sort. If it's nuts 
and bolts, if it's pieces of something she's supposed to assemble, the size of the stimuli may have to be increased to provide 
sufficient contrast for a learner to be successful. 

The final item on our list of variables associated with contrast sensitivity 
is the idea of the complexity of the visual stimuli or the clutter of the visual stimuli with which the is presented. In some 
literature, this is referred to the idea of figure-ground, that the item or the object on which you're attempting to help a learner 
focus needs to be able to stand out from everything in the background. 

Maybe a learner needs to work on a black felt surface with 
red numerals in order to be able to process those numerals. That if you have plywood-colored wooden numerals on a typical student 
desk, or on a desk that has contact paper covering it to control for drool or something, there's too much clutter in that pattern 
of that contact paper. 

And you lose contrast unless you have a brightly colored numeral that is on a black felt surface, or 
something like that. It doesn't have to always be black. I use that as an example. 

But we may have to eliminate clutter, eliminate 
patterned backgrounds, eliminate those visual distractions in order to help provide the contrast-- sufficient contrast-- a learner 
needs in order to process visual stimuli. 

SLIDE 12
The next category of vision loss about which we want to talk for just a few minutes is this notion of processing difficulty. 
On your screen, on the slide, you'll see Processing Problems, and then in parentheses, CVI. CVI stands for Cortical Vision-- 
or Cortical Visual Impairment. And what this refers to is limited and/or inconsistent vision due to the learner's brain not 
properly processing information it receives. This is very complicated. But there are a couple of aspects that are really important 
for family members, for teachers to bear in mind if you see a reference to CVI or cortical vision impairment in a learner's records. 

SLIDE 13
When a learner is diagnosed as having CVI, the problem lies in the learner's brain. The problem lies in the learner's visual 
cortex or in the visual pathways to the visual cortex. The anatomy of the learner's eyes themselves is not impaired. The optic 
nerve that takes what the eyes receive and sends those messages to the brain is not impaired. The challenge, the problem, the 
limitation happens in the processing in the brain. 

And we as teachers, we as family members, we can't get inside the child's head. 
We can't get inside the young adult's head to see what's going on, to understand what's going on. I think what is the most 
important for us to realize is that for a learner who is accurately diagnosed as having CVI, her performance might vary from day to day. 
It might vary significantly from day to day. It might even vary significantly from hour to hour. And this can be incredibly frustrating. 
But if it's incredibly frustrating for us as those individuals who are trying to teach a learner, how frustrating must it be for 
the child or the young adult? 

What I'm referring to is, you might hold up a picture of a car and ask the child to sign or to say 
to you "car" or to match that picture-- even if they can't name the picture, to name the picture to another picture of a car or 
to match little metal cars one to another. And the child might be able to do that sometimes, because the visual cortex, the 
visual pathways are processing what the eyes see accurately, thoroughly, and completely. And other times, the child won't be 
able to tell you "car" or might be able to match but not tell you "car." The performance based on vision can be very inconsistent. 


And this is a very tricky situation with which to deal, because oftentimes, we as the adults tend to say the learner's not 
trying, or it's behavior. The learner's not behaving. The learner's not cooperating. The learner isn't doing her best when 
honestly, she may be doing her absolute best, but her brain isn't processing the visual information in exactly the same way 
it did three hours ago or two days ago or last week. So learners who are correctly diagnosed as having CVI will show in 
many areas of the curriculum, in many aspects of communication that deal with visual supports, visual schedules, they will 
typically show inconsistent performance. They might be able to do things some of the time and not at other times. 

It's 
very frustrating for everybody involved. And I would challenge you to consider this and not just automatically jump to the 
place that, oh, it's behavior, and the learner's not cooperating, and I need to do something to punish that behavior, or 
so on and so forth. If you're talking about a learner who has Cortical Vision Impairment, it really is essential that you 
review the learner's records, talk to the eye care professionals, but most especially in this instance, to talk to the TVI, 
if you've heard that phrase. School systems use that TVI abbreviation to refer to the Teacher of the Visually Impaired. 
He or she will be a great source of information for you in regard to how to handle presentation of materials, presentation 
of instructional aids to a learner with Cortical Vision Impairment, because recent research has shown us that children, 
young adults who experience CVI will oftentimes respond differentially to different colors, to materials that are different 
colors, or to typical classroom materials that are presented on backgrounds of different colors. 

But it's not prescriptive. 
It's not like, oh, red is always better, or yellow is always better, and so on and so forth. Your Teacher of the Visually 
Impaired that works with your child, that works with you if you are a professional in a school system-- that individual is 
your best source of information to do some informal assessments, to give you advice about how you indeed might use color, 
might use presentation of materials to help a child, a young adult, who is challenged by Cortical Vision Impairment. 

SLIDE 14
The final named category of the types of vision loss we'll discuss today is the category on your screen now, ocular motor 
problems-- big word. Take it apart, eye motor. This is difficulty that children have with the muscles that control the movements 
of their eyes. 

A formal definition is to say ocular motor problems involve a learner's difficulty looking at, focusing on, 
and/or following the movement of objects, people, pets, cars, whatever's moving. I think it's not unusual for us to talk about 
the skill of tracking. If a learner can track something that's moving in her field of vision, that's what I mean by following 
the movement of objects and people. If a learner's eyes are not working together in a well-coordinated manner, this very likely 
might involve an ocular motor problem. 

SLIDE 15
There are two types two named ocular motor problems that we wanted to bring to your attention today. Again, big words-- don't be 
intimidated by the words. More than likely, you've encountered the behaviors. The first one on your slide is nystagmus. 

Nystagmus 
involves involuntary rapid movements of the learner's eyes. Usually, the nystagmus involves a side to side movement. It's almost 
as if the learner's eyes are just flipping or flicking back and forth, right to left, right to left really quickly, and that's not 
something that the learner is controlling. It's an involuntary movement if it's in a nystagmus condition. 

If a learner is looking 
from her right to her left and her right to her left, and she's controlling it, that is not the reference here at all. This 
involves an involuntary nonlearner controlled type of movement, which certainly, as we can only well imagine, will interfere 
with what we see and how well we see it. 

The second condition is called strabismus. This is a loss of co-ordinated movement of 
the eyes-- of the right eye and left eye-- which leads to a misalignment. Most commonly, I think in lay person's language, 
strabismus people call the learner's condition as having crossed eyes or a learner being cross-eyed. 

If one learner has a lazy 
eye that drifts to the side, it has to do with the notion that the muscles that control the movement of the learner's right and 
left eyes aren't coordinated. They aren't working together. Those muscles are not working together as they should be, which keeps 
the right eye and the left eye looking together at the same thing at the same time. 

And once again, if you discover one of these 
terminologies in a learner's records, in your own child's records, this is the time that you want to get clarification from your 
child's eye care professional. Sometimes, there is some treatment. One of the most common that you might have encountered is 
sometimes an optometrist, an ophthalmologist, will do patching to try to strengthen one eye for a particular learner while the 
other one is patched so on and so forth. Talk to the eye care professionals on your child's team. 

SLIDE 16
Finally, before we conclude today's discussion, as this slide shows you now, it is important that we remind ourselves that any 
of these vision problems we discussed today might certainly occur in combination. A young child, an adolescent who experiences 
a visual acuity loss and has a condition of partial sightedness might also indeed have a field loss, might also have cortical 
vision impairment. Or a preschooler who has low vision might have incredible sensitivity to light and really need low lighting 
conditions, but also have nystagmus. 

Any combination you could dream of-- I'm sure there is a learner somewhere out there in the 
world that experiences all these different kinds of challenges with their vision. And it is important that we respect them all 
that we as educational teams, we as parents, be aware of them all. A child with multiple visual challenges isn't going to achieve 
to her maximum potential if she has four vision problems and we only deal with the acuity loss. 

Sometimes we have to do things 
in priority order. We can only deal with trying to find answers to one particular challenge at a time. And once again, you want 
to talk to the teacher of the visually impaired, talk to the eye care professional. But we do need to be conscious of every 
single one of these challenges that might occur in combination with the learner. 

SLIDE 17
Before we sign off for today, on your screen now, you see a resource that really is an outstanding resource. It's titled, 
Sensory Perspectives. This is a two CD set that was created by the SKYHIGH Institute at Utah State University. 

I would just 
like to tell you briefly, about the Sensory Perspectives set of materials. On these disks, there are included simulations of 
each type of vision loss we discussed today. There are simulations of partial sightedness, of legal blindness, of light 
perception only, of total blindness. And although we cannot say for sure that what we might see in one of these simulations is 
exactly what a learner experiences, it will certainly help to give us some idea of the challenges that particular learner faces. 


And while I have your attention and am talking to you about the Sensory Perspectives CD, in addition to simulating each type 
of vision loss, these materials also include simulations of each type and level of hearing impairment. And in the series of modules, 
sponsored by the Kansas State Deaf-Blind Project, there is indeed, a module on hearing loss, an introduction to hearing loss. 
There is another module on introduction to deaf blindness. 

So the Sensory Perspectives set of materials might be of interest to 
you in regard to each of those two topics, as well. You can simulate each of the different levels of hearing loss and then, 
when we think about deaf blindness, the Sensory Perspectives CDs offer the user the opportunity to select a particular type of 
vision loss and select a particular level of hearing loss, see those two presented in combination. 

The caution is, we can't be 
sure, we don't know that this is exactly how a particular learner sees and hears because with many of the learners who are 
challenged by deaf blindness, assessments aren't that detailed and that specific that we get exact measures. Even if we had 
exact measures, we can't say the simulation is as good as the real thing, but it can go a long way to helping us understand. 


You may request the Sensory Perspectives materials from the staff of the Kansas Deaf-Blind Project. They'll be happy to provide 
those for your use. They can't provide them to give them to your family or your school district, but you may borrow them. 


I thank you for your attention today.