Rehabilitative Optometric Interventions for the Adult

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Chapter 33
Rehabilitative Optometric Interventions for the
Adult with Acquired Brain Injury
Irwin Suchoff
Rosamond Gianutsos
One prerequisite for rehabilitation of any type is that
appropriate diagnostic measures be undertaken first.
Earlier in this volume (see Chapter 19), Seiller and Warren
discussed issues concerning the screening, evaluation, and
diagnosis of visual system dysfunction, including its high
incidence following stroke, traumatic brain injury (TBI),
and other forms of acquired brain injury (ABI). Nevertheless, even in spite of previous calls (1–8) for appropriate
evaluation and diagnosis, in rehabilitation there is a huge
service delivery problem in that evaluations of the visual
system are minimized, deferred, or narrowly focused on
eye health issues. All too often the patient with ABI has
received an evaluation focused primarily on ocular and
neurologic integrity and health. While these areas are of
prime importance in the immediate posttrauma period, as
the patient enters the rehabilitation arena, other functional
aspects of the visual system become at least equally important. For example, cognitive rehabilitation can be seriously
impeded if the patient is experiencing blurred or intermittent double vision that has not been diagnosed and
managed.
It is important to understand the range of possibilities for intervention, to know how to implement a treatment plan, including which practitioners can be expected
to play which roles, and to evaluate the outcome. It is often
possible to bring about substantial improvement with basic
“bread and butter” interventions, for example, a pair of +1
diopter lenses to give the accommodative-vergence system
the boost it needs to provide binocular vision lost following
608
ABI. Sometimes it is a matter of improving the fit of the
lenses, especially bifocal or multifocal lenses. The high
benefit-cost ratio of optometric intervention is yet another
reason to pursue visual evaluation and rehabilitation.
There are times (e.g., when the patient is languishing
in an ambiguous coma emergent state) when it is just as
helpful to rule out visual problems as it is to identify them.
Here again, the expertise of the rehabilitative optometrist
is invaluable (9).
THE INVOLVED EYE CARE PROFESSIONS
Two professions, ophthalmology and optometry, are currently engaged in the ocular and visual care of the patient
with ABI. Ophthalmology is a specialty of medicine, and
is further divided into subspecialties: cataract, cornea, glaucoma, low vision, neuro-ophthalmology, pediatrics and
strabismus, plastics and reconstructive, retina, and finally
uveitis (10). In terms of the ABI patient, the neuroophthalmologist is most likely to be called on, particularly
in the immediate posttrauma period. At this point, his or
her expertise is essential in terms of patient management.
At times, particularly in the case of accidents, the reconstructive or retinal ophthalmologist is needed. However,
with the exception of the ophthalmologist specializing in
low vision, in practice it is unusual for any of the other
ophthalmologic specialists to play a significant role in rehabilitation. This is not meant to be a negative statement, for
in general, ophthalmology is primarily a medical and surgical discipline. Indeed, the medical school graduate who is
interested in rehabilitation is more likely to opt for a residency in physiatry.
Optometry specializes in primary eye care (11). The
profession’s scope of practice has been significantly
extended with legislation authorizing the use of diagnostic
and more recently, therapeutic pharmaceutical agents.
For the present discussion, there has been and remains a
distinct rehabilitative component in optometry. A prime
example is optometric vision therapy, which has been
defined as the art and science of developing visual abilities
to achieve optimal visual performance and comfort (12).
This is an integral part of optometry in that courses
relating to the anatomy and physiology of the components
of the accommodative and binocular systems, along with
didactic and clinical components relating to the noninvasive therapeutic interventions for these systems, are
included in the curricula of all the optometric educational
institutions. The same case exists for the basic science and
clinical applications of visual perception and low vision.
Optometric students not only must show competence in
these areas in school, but also are tested in this regard by
the National Board of Examiners in Optometry. The profession’s two major organizations, the American Optometric Association and the American Academy of Optometry,
have particular subgroups representing the specialties of
vision therapy and low vision. In addition, three other
organizations, the Optometric Extension Program Foundation, the College of Optometrists in Vision Development,
and the Neuro-optometric Rehabilitation Organization,
are devoted to continuing education and representation of
these areas. Consequently, while the neuro-ophthalmologist
is most likely the eye care professional to be involved with
the ABI patient during the hospitalization period, the
optometrist with interest and expertise in vision therapy or
low vision has been and is increasingly called on by
members of the rehabilitation team, such as the physiatrist,
occupational therapist, physical therapist, and neuropsychologist (5,13–15).
THE INTERFACE WITH COMPREHENSIVE
REHABILITATION
Some larger rehabilitation centers have ongoing relationships with rehabilitative optometrists, who are essentially
integrated into the team. When for a variety of practical
reasons this has not occurred, the physiatrist (as coordinator) and occupational therapist (OT) are most likely to
become involved with issues associated with vision. The
OT’s expertise in the practical, or as they would say functional, implications of interventions. The OT is the past
master of activities of daily living (ADLs) and visual function is crucial to most ADLs. However, any member of the
team should feel free to bring the issue to the attention of
Chapter 33
those who can do something and be prepared to support
the treatment recommendations, even so simple as helping
the patient to put on the correct pair of glasses. The neuropsychologist, speech-language pathologist, and vocational
and educational therapists, who are likely to be working
on reading and other near-point activities, should be well
attuned to adjustments that have to be made for close
vision.
Close working relationships have developed between
OTs and eye care practitioners (1,4); however, at times the
boundaries of professional responsibility are tested. What
then is the role of the OT? In some respects, these practitioners have been the real pioneers who have reached out
to eye care practitioners and encouraged them to become
more involved in rehabilitation. In hospital and residential
rehabilitation settings with no in-house eye care professional, OTs have frequently had to forge links with outside
eye care professionals. In order to rationalize referrals, they
have had to conduct fairly extensive screening procedures,
for example, using stereoscopic vision screeners. This
information has helped them formulate the referral issue
and evaluate the response. When OTs have been able to
accompany the patient to the eye care consultation, they
have been able to assist in the communication of history,
symptoms, and other observations, as well as to bring back
the findings and recommendations to the family and the
rest of the treatment team. However, the independent
spirit that has made it possible for these therapists to bring
these services to their patients has at times led to misunderstanding and the appearance, if not the fact, of overstepping the boundaries of their professional expertise. It is
important for the physiatrist or case manager to recognize
that it is imperative to have a close working relationship
with eye care professionals and to understand the limitations of OTs and other therapists. Important as the OT’s
contribution is, it does not substitute for the active supervision of an eye care practitioner.
OPTOMETRIC REHABILITATION
A general rule for successful rehabilitation is that the caregiver fully discuss the diagnosed condition(s) with the
patient and his or her family or significant others. Not only
should the prognosis be addressed, but also, and perhaps
even more important, is a thorough explanation of the
behavioral and functional consequences of the condition(s).
For example, in the patient with a left homonymous hemianopia (a loss of visual responsiveness on the left side of
the field of view in each eye), one may anticipate frequent
bumping into objects on the left, and ineffective scanning
from the end of one line of text to the next. The individual may appear to “neglect” the left side, when in fact the
problem should be identified as a product of the visual
field cut. There should also be this type of communication
with other members of the rehabilitation team, and other
Rehabilitative Optometric Interventions for the Adult with Acquired Brain Injury
609
health care professionals. For example, the OT or neuropsychologist who is using computer programs for their
aspects of rehabilitation should be fully cognizant that
reading glasses, prescribed for a 20-year-old accident
victim whose accommodative function has been compromised by oculomotor nerve (cranial nerve III) damage,
should be used only for near-point activity, and that the
patient’s vision will be blurred when the glasses are used
for distant vision.
Ocular Health
There is a relatively high incidence of blepharitis with or
without an accompanying dry eye syndrome. Therapeutic
measures for these conditions include patient education for
lid hygiene, including lid scrubs and the use of ocular overthe-counter lubricants. Stroke patients often are diabetic or
hypertensive and consequently are at risk for retinopathies
and cataracts. These patients should be evaluated every 6
months, including with dilated funduscopic examination.
The wearing of glasses with tinted lenses, as well as use of
a hat with a visor, is a valuable intervention to reduce glare
and soften bright environmental lighting conditions that
are a common consequence of cataracts. Further, in the
patient with new or worsening retinopathies, or cataracts
that are compromising the patient’s lifestyle, ophthalmologic consultation is frequently in order.
Refraction and the Prescribing of Glasses
Determining the degree of myopia, hyperopia, and astigmatism can be accomplished by objective means (i.e., static
retinoscopy or automated refracting devices). However,
determining the precise lens prescription is usually somewhat more time-consuming; the objective measures are not
always in concordance with the patient’s subjective experience. Some patients are unresponsive to lens changes over
a relatively wide range, when based on Snellen chart criteria. It is productive to place lenses with the tentatively prescribed correction in a trial frame and engage the patient
in real-life situations. Often, the increased clarity produced
by the lenses will be appreciated when walking down a
corridor, crossing the street, or looking for street signs.
It is essential to place the patient’s refractive status in
the context of the overall condition. Again, assume there is
damage to cranial nerve III; for individuals with myopia of
approximately 2.00 diopters, removing the glasses for most
near-point visual activities is indicated, whereas hyperopes
of any degree should be instructed to wear the glasses for
all visual tasks. Indeed, for many hyperopes with cranial
nerve III damage, a separate reading prescription is indicated. Diabetic patients should be forewarned that their
refractive conditions are subject to change, depending on
the degree to which the diabetes fluctuates (16).
Over the past several decades, great strides have
been made in the options available for the most appropriate ophthalmic lens type for the particular patient. For the
ABI patient, this can be particularly important because of
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the frequent use of prisms to compensate for a binocular
dysfunction or a visual field defect. Prisms can cause chromatic aberrations that are sometimes more noticeable to
the patient than the benefit of more comfortable clear and
single binocular vision or the ability to perceive more of
the compromised visual field. High index lenses afford the
benefits of being thinner and lighter along with physically
protecting the eyes. Lens materials such as polycarbonate
and CR-39 have optical characteristics that can be optimal
for the patient’s refractive condition and for the incorporation of prism into the prescription. Further, antireflective
coatings are a valuable option for the cataract or photophobic patient. Polycarbonate lenses are particularly effective in blocking harmful ultraviolet (UV) rays, which are
etiologic factors in cataract formation and age-related
macular degeneration.
Vertigo
As a result of head trauma or stroke, many patients have
complaints of vertigo. Often, this is a result of a vestibular
dysfunction. Substituting separate pairs of reading and
distant glasses for bifocals helps some of these patients.
Apparently, the head and eye movements involved in positioning the visual axes in the distant or near part of the
multifocal lenses can often exacerbate the vestibular
problem. Further, progressive addition bifocals are particularly disturbing to the dizzy patient; even many non-ABI
patients need to adapt to the aberrations that are a consequence of the optical design of these “invisible” bifocal
lenses. On the other hand, these progressive lenses can
have particular advantages, including having only one pair
of glasses to keep track of, being of variable strength for
intermediate distances, and allowing for convenient adjustment to fluctuating needs.
Photophobia and Related Visual Phenomena
A not uncommon complaint of the ABI patient is an
increased sensitivity to light, both outdoors and indoors.
Further, some of these patients also remark on a perception
of waviness or shimmering that is lessened in decreased
lighting conditions. Lenses that absorb the shorter wavelengths of light (e.g., blue-tinted lenses) can relieve both the
photophobia and the waviness or shimmering in a number
of patients. While the type of tint may be determined by
trial and error, recent research provided objective evidence
to the patient’s subjective reports of decreased symptoms
with light-filtering lenses. Jackowski et al (17), in a controlled
experiment, demonstrated that the use of Corning Photochromic Filtering lenses (CPF 450) increased contrast sensitivity and improved reading rates in TBI patients who
became photophobic after trauma.
Optometric Vision Therapy (Visual Training)
This type of intervention is used to rehabilitate dysfunctions of the dynamic systems of vision, including eye
movements (fixation, pursuit, and saccade), the accom-
Figure 33-1. A. Pretherapy fixational movements of the
right eye. Posttherapy fixational movements of
the right eye without (B) and with (C) the
5.5–prism diopter base-in prism incorporated
into the spectacle correction in each eye.
Binocular viewing in all cases. (Reproduced
by permission from Ciuffreda KJ, Suchoff IB,
Marrone MA, Ahmann E. Oculomotor
rehabilitation in traumatic brain-injured
patients. J Behav Optom 1996;7:31–38.)
modative system, and the binocular system, ranging from
constant strabismus, to intermittent strabismus, to the nonstrabismic anomalies of binocular vision and visual perception (2,18). There is also evidence that vision therapy is
effective in controlling ABI-induced nystagmus (19).
Therapy to stabilize visual fixation ranges from using
techniques that require sustained and accurate central fixation, such as filling in the circular portions of the letters
“o,” “b,” and “d” contained on a newspaper page with a
sharpened pencil, to using computer-based programs that
require the patient to maintain fixation on a specific
portion of the monitor screen, and respond by hitting the
space bar or mouse when a predetermined number
appears (20). The efficacy of such a regimen has been
demonstrated by electronically based eye movement
recordings (15) (Fig. 33-1).
Pursuit and saccadic eye movements are frequently
impaired following ABI (21,22). When the latency and
accuracy of these eye movements are compromised, the
results can be devastating. Thus, the not infrequent observations of some ABI patients that they see the car while
crossing the street, but cannot follow it . . . “I lose where
it is” . . . can often be attributed to delayed or inaccurate
Chapter 33
visual pursuit. Saccadic eye movements are a prerequisite
not only for accurate and effortless reading, but also for
accurately sampling a new visual environment. Ron (23,24)
conducted visual training with several TBI patients and
gave objective evidence via infra-red eye movement recordings of enhanced pursuit and saccades. Further, he demonstrated that the improvements were beyond those
attributed to the healing process.
Therapies to rehabilitate saccade and pursuit movements have long been an integral part of optometric vision
therapy. In general, the goal is to equalize and maximize
the performance of each eye as to latency, accuracy, and
automaticity, in a purely visual fashion, that is, without
active body, neck, or head movement. Then one proceeds
to binocular techniques. Further, techniques to improve
proprioceptive and kinesthetic awareness, or “feeling” of
the extraocular muscles are used to enhance performance.
Therapy proceeds from low to higher cognitive tasks as the
individual gains increasing control over the saccade and
pursuit movements. A popular technique for saccade
therapy is the use of various electronically based devices
that program random sequences of small light sources,
which the patient is instructed to touch as each is lit.
The speed and spatial complexity can be varied. Other
advanced therapies for pursuits and saccades are available
in computer programs that can be used for in-office and
home procedures, some of which are listed in Table 33-1
(25). Others are described later in the section on interventions for visual field impairment.
Dysfunctions of the accommodative (focusing) mechanism are not uncommon in ABI patients (26). While the
obvious immediate causes are trauma to cranial nerve III
or the ciliary muscle, persistent accommodative dysfunctions (e.g., amplitude, flexibility, or sustenance) can be a
consequence of anticholinergic or other medications that
affect the parasympathetic nervous system. There is
general agreement that the primary therapeutic measure is
to prescribe the indicated convex lens power that enables
the patient to attain clear near vision (8,27). Incorporating
techniques that enhance all aspects of the accommodative
response, such as decreasing latency and increasing flexibility, are often effective. These techniques challenge the
ability of the patient first to quickly clear targets at near,
then at far, and so on. The next step is to sustain clarity of
the near target for increasing periods of time, and then
instantly to clear the far target, and sustain its clarity for
increasing periods of time, and so on. This type of
“accommodative rock” can be carried out in free space, or
with the aid of lenses, or lens and prism combinations (28)
(Fig. 33-2). During the therapy, the patient’s accommodative abilities should be closely monitored so that as
improvement occurs, the convex lens prescription can be
appropriately decreased in power.
Dysfunctions of the binocular system can be conceptualized on a continuum from constant strabismus, to
intermittent strabismus, to nonstrabismic anomalies of
Rehabilitative Optometric Interventions for the Adult with Acquired Brain Injury
611
Table 33-1: Computer Resources for
Optometric Rehabilitation
NAME
Computer
Orthoptics
Block
Breaker
Functional
Visual
Fields
BISECT—
Line
Bisection
OPTOMEX—
Optometric
Scanning
VISMEM—
Visual
Memory
Jigsaws
Galore
Visual
Perception
Vision 3D
Project
Gutenberg
VS
Memory
Jiggler
Morejongg
Computer
Aided
Vision
Therapy
a
b
c
AUTHOR(S)
SOURCE
J. Cooper
American Vision Therapya
Y. Emura
http://www.emsoft.co.jp/block-e.htm
R. Gianutsos
Life Science Associatesb
R. Gianutsos
Life Science Associatesb
R. Gianutsos
Life Science Associatesb
R. Gianutsos
Life Science Associatesb
D. Gray
http://www.dgray.com/jigalo.htm
S. Groffman
American Vision Therapya
M. Grossman
& R. Cooper
—
http://www.vision3.com
http://www.promo.net/pg/
G. Kerkhoff
and C.
Marquardt
S. Moraff
J Neurosci Methods
1995;63:75–84
S. Moraff
G. Vogel
http://www.moraffware.com
Bernell Corporationc
http://www.moraffware.com
Figure 33-2. In the accommodative rock exercise, the
patient holds “flipper” lenses that contain
additional plus (magnification) lenses in one
pair and additional minus lenses in the other.
The task calls for attaining a clear image
through one set of lenses and then flipping
the lenses and using accommodation to attain
a clear image as efficiently as possible. In the
present illustration, an eye patch is worn and
the exercise is monocular.
American Vision Therapy, PO Box 197, Cicero, IN 46034. Tel: 800346-4925.
Life Science Associates, 1 Fenimore Road, Bayport, NY 11705. Tel:
516-472-2111. Also, at Web site http://www.lifesciassoc.home.
pipeline.com.
Bernell Corporation, 750 Lincolnway East, PO Box 4637, South
Bend, IN 46634-4637. Tel: 800-348-2225.
binocular vision (Fig. 33-3). Patients with strabismus resulting from ABI most often do not make the adaptations that
classically occur; there is little or no suppression-based
amblyopia, or anomalous correspondence. Rather, even
years after the accident or stroke, patients who are diplopic
are told to either patch one eye or to “learn to live with
it.” One strategy has been to provide the patient with
prism lenses that compensate for the eye turn, and then
institute usual vision therapy to develop binocular vision
(29). Basically, this is done by establishing single binocular
vision with the eye in the primary position and the patient
wearing the prism correction and then developing vergence binocular eye movements opposite to the direction
of the turn (e.g., divergence in the case of esotropia, and
convergence in exotropia). The primary method is to
provide each eye with a discrete target that when combined with its counterpart, results in a meaningful visual
percept. A number of devices have been developed for
these purposes, so that it can be accomplished “in instrument” or in “free space” (Figs. 33-4 and 33-5). Targets that
require various levels of binocular vision (i.e., superimposi-
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Therapeutic Interventions
Figure 33-3. Continuum of dysfunctions of the binocular
system. (Reproduced by permission from
Suchoff IB, Petito GT. The efficacy of visual
therapy: accommodative disorders and nonstrabismic anomalies of binocular vision. J Am
Optom Assoc 1986;57:119–125.)
tion, fusion, and stereopsis) are available. As the patient’s
ability in these tasks increases, it is usually possible to
decrease the amount of prism in the patient’s glasses.
When it is believed that further progress cannot be made,
active vision therapy is ceased, and the patient is monitored on a regular basis. In this manner, the patient is
diplopia free without the use of a patch.
However, when further progress is possible, the same
regimen is used for nonstrabismic anomalies of binocular vision.
Table 33-2: An Expanded Classification of
Vergence Dysfunctions
Fusional vergence dysfunction (skills case)
Convergence insufficiency
Pseudoconvergence insufficiency
Convergence excess
Divergence excess
Divergence insufficiency
Basic exophoria
Basic esophoria
Figure 33-4. The troposcope is a device that allows one to
present images to each eye and to determine
precisely the separation of the two images.
This separation corresponds to the deviation
between the eyes in the absence of external
stimuli that could promote fusion.
Figure 33-5. Worth 4 Dot test. The examiner shines a
flashlight adapted so that it shines lights of
red, white, and green. The examinee wears
red/green anaglyphic glasses over the
customary prescription. Under these
circumstances, a person who uses both eyes
will see all the lights.
This umbrella term classically encompasses the various
vergence dysfunctions, for example, convergence and divergence insufficiency and excess, and vertical phorias for
which the patient cannot compensate. However, an
expanded classification has developed over the years (Table
33-2). Regimens and procedures to remediate these conditions have been fully described in the optometric literature
(1,30–32). Further, once the patient has achieved sufficient
binocular skills, exercises can be based on the stereograms
available in popular books and computer programs (e.g.,
Chapter 33
see Web page at http://www.vision3d.com). It is usually
not difficult to motivate patients to use these attractive
materials. The basis of these therapies is to maximally
develop the quality, range, and sustenance of comfortable
clear and single binocular vision by sequentially increasing
the complexity of the cognitive and sensory-motor
demands.
While the synkinesis between accommodation and
convergence is certainly a consideration in strabismic
therapy, it takes on a key role in the rehabilitation of the
nonstrabismic anomalies of binocular vision. Hence, the
ultimate goal of therapy is to normalize this relationship,
that is, to develop an appropriate or expected accommodative convergence to accommodation (AC/A) ratio. This is
accomplished by developing a freedom between the two
functions. In this instance, the patient is given techniques
where, for example, convergence must be inhibited, in the
interest of single vision, while accommodation is stimulated, or where accommodation is inhibited while convergence is stimulated. These techniques require the use of
lenses or prisms that vary the accommodative and vergence demands, respectively.
In one of the best controlled efficacy studies,
applying the single case experimental design, Kerkhoff
and Stogerer (33,34) trained fusional convergence using
three orthoptic devices (fusion trainer, prisms, and cheiroscope). Eleven of 12 ABI patients showed 1) no gains in
baseline, 2) gains during treatment, and 3) maintenance of
gains during a 10-month follow-up period. They also
experienced gains in near-point acuity, stereopsis, and
reading, together with a reduction in subjective symptoms
associated with fusional deficiency (e.g., eyestrain and
headache).
In general, there is increasing utilization of vision
therapy for ABI patients. Morton (35), an ophthalmologist,
proposed that this therapy uses repetition to retrain neural
pathways that have been damaged, or to develop alternative pathways, and presented several case studies. Freed
and Hellerstein (36) presented a more scientific demonstration of the efficacy of this type of optometric intervention.
An experimental group of 18 patients with mild brain
injury received a regimen of optometric rehabilitation,
while 32 matched control subjects did not. At 12 to 18
Rehabilitative Optometric Interventions for the Adult with Acquired Brain Injury
613
Table 33-3: Functional Visual Field
Assessment Procedures
PERIPHERAL (TO 20 DEGREES)
REACT: Reaction Time
Measure of Visual Field
SDSST: Single and Double
Simultaneous
Stimulation
SOSH: Search for the Odd
Shape
SEARCH: Visual Search
PERIFOVEAL (CENTRAL 4
DEGREES)
INSPECT: Shape Inspection
FASTREAD: Tachistoscopic
Reading
ERROR DETECT: Error
Detection in Texts
Source: Life Science Asssociates, 1 Fenimore Road, Bayport,
NY 11705. Tel: 516-472-2111. Web site:
lifesciassoc@pipeline.com.
months after therapy, the experimental group showed a
significant decrease in pattern visually evoked cortical
potential (VECP) abnormalities, as opposed to the control
group.
Rehabilitation of Visual Field Impairments
Following brain injury, visual field impairment is fairly
common, yet it is often undiagnosed or underdiagnosed.
These problems are usually characterized by a lateralized
differential pattern of response to visual stimuli. The loss
may be relative or absolute, and the problem may involve
the central ( perifoveal) or the peripheral fields, or both.
Formal optometric diagnostic procedures, detailed
elsewhere (5), include perimetry for the peripheral fields
and testing using the Amsler grid for the central fields.
Unfortunately, these assessment procedures present cognitive demands, which can limit their use with the ABI
patient. Specifically the individual must sustain a focus of
attention on a fixation point, while reporting on perceived
events elsewhere in the field of view. In the case of threshold perimetry, in which the minimum light intensity seen at
each point is mapped, these decisions may involve fine discriminations and rapid judgments. To help meet this diagnostic challenge, Gianutsos and Suchoff (5) recommend a
modified two-person confrontation procedure and computerized functional visual field tests with norms (37).
Functional Visual Field Procedures
The functional visual field procedures, listed in Table 33-3,
require responses to visual stimuli throughout a computer
screen. In most instances, there is no fixation requirement
and the speed of response to stimuli in different locations
is measured. The functional visual field procedures have
proved to be simple enough for most ABI patients to do
and there are norms for both young and old adults (37).
The procedures for the peripheral fields address responsiveness to the near periphery (about 30 degrees) and
range from attentionally simple [e.g., Reaction Time
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Therapeutic Interventions
Figure 33-6. SOSH (top panel) and SEARCH (bottom panel)
displays. With SOSH (Search for the Odd
Shape) the task is to point to the shape
(“Martian face”) that is different (“sleeping”),
in this case in the upper left of center. For
SEARCH, one is to point to the shape in the
peripheral array that matches the center shape
exactly, again in the upper left. The examiner
moves the center box with the arrow keys.
Response time is the time from the stimulus
onset to the beginning of a move that
ultimately reaches the target.
Measure of Visual Field (REACT)] to complex [e.g.,
Search for the Odd Shape (SOSH) and Search for Shapes
(SEARCH)], illustrated in Figure 33-6.
There are also functional visual field procedures for
the perifoveal (central 4 degrees) fields: Shape Matching
(INSPECT), Tachistoscopic Reading (FASTREAD), and
two alternative forms of Error Detection in Texts (38). For
assessment purposes, normative information is available
(39). INSPECT (Fig. 33-7) requires a rapid same or different judgment and no verbal ability. In FASTREAD (Fig.
33-8), isolated words are flashed on the computer screen
and the examinee says or types them. The procedure is
adaptive in that following correct responses, the next
item is presented faster and following incorrect ones, it is
frames as they remain more consistently in place. Small
oval lenses have less optical distortion and are lighter.
Often the best response to these lenses is subjective,
although the patient should be prepared not to expect a
cure. Further, since the optical interventions do not fully
correct the loss, it is essential to complement this intervention with awareness counseling, practice with feedback,
and training in compensatory scanning.
Counseling
presented more slowly. The nature and pattern of errors
are analyzed. For example, POLICE may be changed to
“POLICY,” a right substitution, or to “LICE” a left truncation. Following brain injury, substitutional errors are
more common than truncations and probably reflect
macular sparing. Error Detection in Texts (Fig. 33-9) calls
for proofreading of continuous text and affords a sensitive
index of perifoveal hemi-imperception. Although errors
are distributed equally on the left and right sides of the
page, more often than not, the critical factor is whether the
error occurs at the beginning or end of the word.
Typically, visual hemifield impairments caused by central
nervous system injury are exacerbated by a loss of awareness. It is important to understand that this lack of awareness is inherent to some forms of sensory loss, as when the
person with a hearing loss thinks others are not speaking
clearly. Gianutsos (41) parallels this phenomenon with the
unawareness all of us have for the rather substantial (the
size of a fist at arm’s length) visual field loss corresponding
to our physiologic blind spot. She contrasts this with the
heightened response to glare, which triggers immediate
attempts to avoid or control. While this unawareness of
neurologically produced visual field losses is sometimes
profound, more often it is expressed as an underappreciation of the magnitude of the problem. Accordingly, there
is much misinterpretation of the patient’s behavior, and
safety is compromised (42). It is therefore essential that
rehabilitative interventions address the awareness issue.
While a true subjective awareness of the lost vision often
does not develop, as it would for a cataract or a retinal
defect, it is possible for the patient to develop an intellectualized awareness of the problem. In other words, they
can learn that if they cannot locate something, then it
must be in the area covered by the visual field defect.
Therefore, treatment must be directed toward increasing
awareness of the visual field problem to the extent that it
cannot be treated optically and by developing compensatory eye movements.
Optical Interventions for Visual Field Loss
Practice with Feedback
Until fairly recently, rehabilitative interventions for visual
hemifield impairment were limited to counseling and compensatory training. Fortunately, optical interventions are
now being refined to complement, if not correct the
problem. Optical interventions for visual field loss,
reviewed by Cohen and Waiss (40), involve the use of displacing prisms or spectacle-mounted mirrors. Ground-in
yoked prisms in the range of 6 to 12 diopters appear to be
most useful. The base of each prism is placed in the same
lateral direction in relation to the patient. In other words,
the displacement is in the same direction in each eye. A
pair of spectacles designed for a stroke survivor with an
upper-right-quadrant field loss is illustrated in Figure 3310. A different set of glasses with greater prismatic power
than would be used for distance may be necessary for
near-point work. The fit of the spectacle is important.
Here we would especially recommend spring-loaded
Exercises that offer feedback organized by the location of
the stimuli are useful for building both skill and awareness.
Examples include cancellation (43,44), Error Detection
in Texts, and common word-search and hidden-figure
puzzles. These, especially error detection, tend to focus on
central field impairments. Practice materials for error
detection (38) can be created from texts downloaded from
sources such as Project Gutenberg (see Web site
http://www.promo.net/pg/), including famous speeches,
short stories, and even whole books. These can be reformatted and edited with a word processor, as illustrated in
Figure 33-9. Advanced computer spelling checkers, which
highlight incorrectly spelled words, are particularly convenient for the creation of these materials, as one can see the
errors and their distribution on the page.
Computerized tasks can have special value by offering immediate feedback to promote the development of
Figure 33-7. INSPECT display. The task is to press the left
or right side button to indicate if the
difference in the two shapes is on the left or
right side. The computer reports decision
times for stimuli that differ on the left and
right.
Chapter 33
Rehabilitative Optometric Interventions for the Adult with Acquired Brain Injury
615
Figure 33-8. FASTREAD (Tachistoscopic Reading)
printout. The display time
(horizontal bar) decreases following
correct reading, setting after a series
of trials at an asymptotic level
(“consistently best time,” here
approximately 0.04 second). The
subject types the word seen and
errors are printed for subsequent
analysis. In this instance the
individual has a profound macula
invading homonymous right-upperquadrant hemianopia (see Fig. 3310), reflected in end of word
substitutional (“CHAIR” Æ
“CHAIN”) and truncational (“BAND”
Æ “BAN”) errors.
awareness. The computerized functional visual field tasks,
described earlier, can be used for this purpose, as they offer
different random versions on each administration. They
also offer the individual opportunity to practice compensation and to determine the limits of compensation.
Training in Compensatory Scanning
Many tasks can be used as a tool for compensatory scanning. The classic task for nonaphasics is reading, both out
loud and silently. Reading addresses the integrity of both
the central fields (reading words accurately) and the
peripheral fields (returning to the margin for left hemianopics reading languages that are printed from left to
right and overall speed of reading for right hemianopics
who have trouble scanning rapidly into their blind field).
Weinberg et al (45) suggested the use of a colored line in
the left margin to provide an anchor for left hemianopic
readers. This technique can be very helpful for those who
have peripheral field involvement.
Other visually complex tasks, such as completing
mazes and jigsaw puzzles, are useful in building visual field
scanning skills. Computerized versions of these tasks
abound, and are becoming more and more visually rich
with improved computers. A feature common to these
tasks is the use of a computer mouse (or, often better for
616
Part III
Therapeutic Interventions
persons with limited motoric control, a trackball) to control
the cursor on the screen. Developing the eye-hand coordination necessary for controlling the cursor in this fashion
may be a special challenge for patients with visual field
problems. Frequently it is a good idea to begin with a
simple solitaire game on the computer—an insight that
computer software manufacturers have long recognized,
since solitaire is supplied with just about every computer
that has a graphic user interface!
A dynamic scanning task, widely available under
many names is Breakout. This task is like playing tennis off
a backboard, except that the board is an array of bricks,
which are removed by hitting them with the ball. The
lateral movement of the paddle is typically under mouse
(trackball) or joystick control. We use a “freeware” version
(shown in Fig. 33-11) called BlockBreaker (see Web site
http://www.emsoft.co.jp/block-e.htm) because it is very
plain, has parameters affording a wide range of difficulty,
and supplies meaningful scores.
A favorite among these computer exercises (or
games) is Mahjongg, which goes under different names,
such as Taipei, Shanghai, and Morejongg. This shapematching exercise is visually appealing and presents constraints that challenge logic and sequencing. Morejongg
(see Web site http://www.moraffware.com) is a multimedia
Figure 33-9. Error Detection in Texts. In the
example there are 20 errors, half
on the left and half on the right.
Half of each of these is at the
beginning of the word and half at
the end. This famous text was
downloaded from the Gutenberg
Project Web site
(http://www.promo.net/pg/),
reformatted, and edited with a word
processor.
version of this exercise that offers rich visual and auditory
inducements to engage in the exercise (Fig. 33-12). Further,
it yields scores (time and number of pieces remaining) that
can be tabulated. The clinician enters this information on
a spreadsheet that computes a rate of matching and a
graph (Fig. 33-13) that reveals an overall trend, which can
be very motivating for the patient (and the insurance
company!).
Jigsaws Galore (see Web site http://www.dgray.com/
jigalo.htm) is a program that preserves most of the features
of the classic noncomputerized game and adds some useful
ones. For instance, it keeps track of the time and number
of pieces put together, information that can also be converted to a solution rate index and graphed. As illustrated
in Figure 33-14, one can make jigsaws out of virtually any
picture, including family photographs and scenes varying
in complexity. Furthermore, the number, size, and orientation of pieces can be specified so that the difficulty can be
controlled over a broad range. Like Mahjongg, the fun
index for this exercise is high and patients engage in it
eagerly on their home computers.
Chapter 33
The value of the computer is that it is dynamic, it
keeps track of performance automatically, and it is appealing. While the computer is not for everyone, it is a tool that
can be invaluable. There is, however, no risk that the computer will replace therapists. While the computer may
extend what is possible for therapists to do, the therapist is
crucial in identifying appropriate tasks and parameters,
introducing them and helping the patient to appreciate
why the task is useful, advising on what methods should be
used to improve performance, and counseling regarding
the implications of the results.
Efficacy studies substantiating these techniques
for promoting visual field awareness and compensation
have been published by Kerkhoff and his colleagues
(46,47), Scherzer (48), and researchers at the Rusk
Institute in New York (43,45,49). Encouraging as these
studies are, it is well to appreciate that visual field impairment remains one of the more challenging problems for
optometric rehabilitation. The problem may persist and
the individual lulled into thinking that the problem has
been overcome. It is often useful to offer “booster doses”
Rehabilitative Optometric Interventions for the Adult with Acquired Brain Injury
617
Figure 33-10. Spectacles (upper panel) with a yoked (bases
up and right) prism used to assist an
individual with an upper-right-quadrant
(lower panel). The prisms displace the image
down and to the left. In these reading
glasses, the strength of the prism is greater
than for distance viewing. Note that the
visual fields shown are for the central 4
degrees and clearly show only a degree of
macular sparing.
Figure 33-11. BLOCKBREAKER display. The bar at the
bottom is the paddle that is controlled by
rolling the trackball (or mouse) to the left
and right. As the ball hits the bricks, they
are removed. The ball bounces off the walls
and the observer must engage in rapid visual
pursuit, much as in the game of paddle
tennis. The score is the number of bricks
removed.
Figure 33-12. Mahjongg starting display from the program
Shanghai: Dragon’s Eye (Activision, Inc.).
Visually, this stack of 144 attractively
colored tiles is viewed slightly from the left.
In computerized Mahjongg, the object is to
match identical tiles, with the constraint
that a piece cannot be covered by another
piece and it must have a left or right edge
exposed. Here the center (also the top of the
stack) tile (eight balls) could be matched
with one in the second row on the right, but
not with the one in the third row from the
bottom. As the exercise progresses, the
computer reports the number of shapes
remaining and elapsed time. From this,
solution rate is the ratio of shapes matched
per unit time.
Figure 33-13. Progress on computerized Mahjongg of a
patient after right-hemisphere
cerebrovascular accident who has dense left
homonymous hemianopia. For the most part,
there was one session per week, although
later on there were two sessions on 1 day. To
minimize acuity issues, sessions 1 to 85
were conducted with tiles containing a large
letter (disigned like a child’s alphabet
block). The dip at session 86 reflects the
beginning of the more visually complex tiles
shown in Fig. 33-12. The overall trend
shows distinct progress; however, there was
much session-to-session variation.
CONCLUSIONS
Importance of Comprehensive Evaluation
All too often following brain injury, visual problems remain
undiagnosed. Diagnosis is a prerequisite for systematic
rehabilitation to occur. Early, appropriate, and comprehensive evaluation is essential because of the primacy of vision
in information processing and many visual problems do
not reveal themselves subjectively.
Rehabilitative Optometry
Rehabilitative optometrists are the key service providers for
such comprehensive diagnosis and functionally oriented
treatment planning. They work most closely with OTs,
physiatrists, neuropsychologists, and physical therapists,
and are becoming an integral part of the treatment team.
Consultation with ophthalmologists is appropriate when
there is a need for ocular surgery or for the treatment of
complicated ocular pathologies.
Figure 33-14. JIGSAWS GALORE, a computerized jigsaw
puzzle. The pieces are moved by “dragging”
them with the trackball or mouse, that is,
pointing the cursor arrow to the desired
piece, holding the button, moving the piece
to the desired location, and releasing the
piece. Correct juxtapositions are reinforced
by an audible click and linking together. The
computer reports the number of pieces
solved and the solution time. One can create
puzzles out of any computer image file and
designate a wide range of difficulty (number
of pieces). In the present instance, all
pieces are shown in their correct orientation;
however, one can allow rotation as an option.
(Reproduced by permission from David Gray,
http://www.dgray.com/jigalo.htm.)
of tasks with feedback to counter this tendency. Periodically, the individual with persistent visual spatial hemiimperception needs to be reminded of the limits of
compensation.
Visual Rehabilitative Interventions
Interventions include the treatment of ocular disease, prescription of lenses and prism, vision therapy, patient and
family education and counseling, and environmental modifications. Computerized visual tasks have particular value
as a therapy tool. Often conventional interventions (e.g.,
properly fit spectacles with correction) are overlooked or
incorrectly applied following ABI. These all too common
failures in the implementation of standard eye care occur,
perhaps, because of the need for special clinical skill with
this population.
Efficacy
Efficacy studies offer support for these approaches. The
most difficult conditions to treat include visual field loss
coupled with hemi-inattention, significant nystagmus, and
optic nerve atrophy. In most instances, however, results
range from at least helpful to, in some patients, a complete
functional solution.
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