PrinciplesofOptometricRehabilitation

Joel H. Warshowsky, OD, FAAO

INTRODUCTION
Rehabilitative disorders, often of congenital or genetic
etiology, I include delay in development, cerebral palsy,
spina bifida, chromosomal disorder, hearing impairment,
mental retardation, and agenesis or failure to thrive. The
Administration on Developmental Disabilities estimates
that two of everyone thousand adults have a developmen-
tal disability,2 and that approximately 12% of children in
the United States are educated in special programs.
2
Post-
birth brain trauma can be caused by stroke, tumor, or head
injury.3 Each year approximately 900 000 cases of closed
head trauma are treated in hospital settings, of which 75%
of patients survive and require some form of rehabilita-
tive therapy.3 Seizures, resulting from such pediatric
illnesses as rubella, encephalitis, and pneumonia, can
become sequelae of neurological dysfunction.
4
-
6
Vacci-
nation (DPT), and to some degree allergy, may also play
a role in ophthalmic neuropathy.6 Other conditions that
require rehabilitative therapy throughout adult life in-
clude multiple sclerosis and Parkinson's and Alzheimer's
disease.
6
The high prevalence of visual problems in these
populations has been previously cited,I-4 and prevalence
rates vary with the condition. For example, the preva-
lence of refractive anomalies has been found to be greater
than 50% in children diagnosed with mental retardation,
cerebral palsy, and Down's syndrome, but only 20% to
30% in hearing-impaired children.
2
The most frequently
occurring visual problems diagnosed in patients with
secondary visual anomalies are refractive error and stra-
bismus; other common visual conditions include oculomotor
dysfunction and inefficiency, accommodative insuffi-
ciency, infacility and excess, convergence insufficiency,
binocular instability, and lags in motor planning and
spatial organization.
7
-
9
Optic neuritis, conjunctivitis, and
visual field defects have also been noted. I
Optometrists can provide rehabilitative therapy for
patients with secondary visual anomalies in a variety of
institutional settings, including hospitals, schools, and
remedial centres.
IO
-)3 Through such remedial optometric
intervention optometrists have the unique opportunity of
positively affecting patients' behavior by way of a sen-
JH. Warshowsky - Chief, Pediatric Unit, College of Optometry, State
University of New York, New York, New York
4 Practical Optometry 4: 1, 1993
sory system that is purported to have significant control
over primary information processing
14
AMODEL OFVISUALFUNCTION
Classically, visual function has been described in terms
of two processes: primary visual processing and associa-
tive visual processing. Primary visual processing func-
tions through oculomotor, accommodative, and binocu-
lar systems (basic ocular skills).15 Associative visual
processing denotes the visual-perceptual aspects of vi-
sion, which include the organization of information re-
ceived, its integration with other sensory and motor
systems, and its retrieval for the utilization of overt
behavior. 15
It is my opinion and that of others in the fields of
optometry and occupational therapy that deficits or limits
in primary visual processing result in dysfunctional asso-
ciative visual processing. 15.16 Optometrists thus must evaluate
and remediate the underlying skills associated with pri-
mary visual processing first, i.e., prior to the higher-level
processing skills of visual closure, form reproduction,
spatial organization, visual memory, and the integrated
skills of visual, motor, and auditory processing.
16
Both
primary and associative visual processing difficulties are
common in patients with secondary visual anomalies.
As part of a multidisciplinary team treating these
patients' gross, fine, and visual motor functions, the
optometrist must assess the associative process in order
to monitor and manage change in function. These
multidisciplinary programs, affected by occupational,
physical, and cognitive therapists, often interrelate idea-
tion and motor-planning activities with proprioceptive
feedback.
17
Also involved in the rehabilitative process
are speech and language pathologists, who support the
process of communication skills.
17
EVALUATING PATIENTS FOR
VISUAL REHABILITATION
Prior to determining whether such techniques as patch-
ing, lenses, prisms, and vision therapy can be effective
intervention strategies, the optometrist must assess whether
or not the patient's visual function is capable of remediation
or normalization. Remediation represents treatment that
cures or relieves through nonadapted behavior, whereas
normalization represents improved function through
Fig. 1Communication board devices
adapted mechanisms. Philosophically, it is thought that
systemic functioning is capable of remediation unless
certain factors are involved, such as p'hysical disability,
long-standing dysfunction, traumatic injury, congenital
defect, and limited function resulting from previous
surgical intervention.
The optometrist may need to modify the evaluation
in order to ensure that visual function can be best assessed
with the greatest degree of freedom from the patient's
associated condition. IS An organized examination room
equipped with hand-held instruments is a necessity. For
patients who are distractable, a small, darkened room and
soft-spoken instructions may be required for reliable and
consistent responses. IS Communication boards (Fig. 1)
utilized for discrimination procedures help to elicit reli-
able responses during visual acuity and accommodative
testing.
4
,'6"s Patients may be positioned in their wheel-
chair, enabling appropriate head, neck, and trunk control.
In addition, some children benefit from being examined
in a supine position, 18 Body and head restraints should be
kept to a minimum, if possible, to allow the foundation of
fovea to target to be made.
'8
.
'9
The two most important clinical questions to address
in evaluating for visual rehabilitation are the amount of
vision available to the patient and the extent to which
other rehabilitative conditions caused by the visual dys-
function are present. Answers to these questions begin to
unfold from the first moment of contact with the patient.
I,
Consideration of the patient's development, neurological
function, heredity, ambulation, and cognitive ability all
weigh in the analysis. Knowledge of the patient's fetal
and birth history clarifies the patient's overall condition
to enable correct visual rehabilitation. Additional insights
should be gained from previous reports from the patient's
I.
neurologist, ophthalmologist, occupational and physical
therapist, speech pathologist, special educator, psychologist,
social worker, and primary-care physician.
When asking questions of the patient, care must be
taken that the patient be treated in a manner commensu-
rate with his or her capabilities, and a reassuring ap-
proach will foster both trust and the perception that
caring, sensitivity and respect for the patient exist.
Occupational therapists often accompany patients to
their optometric evaluation, and may offer invaluable
perceptions on the patient's motor, sensory, and neuro-
logical development. For example, an entry sheet has
been developed for cerebral palsy patients to assist the
optometrist in gaining additional history and background.
4
This may be modified to suit various rehabilitative con-
ditions. Conversely, the ability of the patient's occupa-
tional therapist to readily grasp pertinent optometric
information is essentiaJ.1
Visual Acuity
Not all rehabilitation patients will respond to conven-
tional Snellen acuity chart testing.
21
In the evaluation of
nonverbal patients, matching on a communication board
using targets of letters, numbers, and pictures can be
helpfuI.
4
.
'6
,'8 Symbol charts which are often used include
the Tumbling E, Landolt C, Broken Wheel,22 Allen
cards,23 and Parson's acuity tests
24
The Light House
cards have become my standard choice. Individual pic-
tures of a house, apple, and umbrella can be presented at
10 feet and at 16 inches, Noncommunicative patients may
be presented with the Forced Preferential Looking (FPL)
technique.
25
Response to a patterned field over a homo-
geneous field can be graded into an acuity measure. In
nonresponsive patients, a Visual Evoked Potential (VEP)
provides an objective electrodiagnostic measure ofmacular,
optic nerve, and visual cortical function,26
Ocular Motility
An assessment of ocular motility must begin with the
patient's ability to fixate on a target. Fixation is assessed
through the Hirshberg technique
27
utilizing a white light
transilluminator. This objective technique evokes reli-
able responses. Once fixation has been attained, tracking
in all meridians of gaze is attempted via a light target.
Limitations, nystagmus, noncommitancy due to muscle
paresis, and inefficiencies are noted. The New York State
Optometric Association (NYSOA) King-Devick Test
28
or
the Developmental Eye Movement Test (DEM?9 is use-
ful in demonstrating change in performance over time,
Binocularity
When rehabilitation patients are incapable of conven-
tional binocular testing, a modified assessment often can
be aChieved. Near point of convergence and distance and
near cover testing utilizing the Hirshberg technique will
yield significant visual and postural information when
combined with previous motility testing. Assessment of
Optometric Rehabilitation - Warshawsky 5
fusion must consider the presence of strabismus,
noncommitancy, fusional reserve, and motor compensa-
tions such as torticollis and head turns.
Accommodation
Patients who do not respond to traditional accommoda-
tivetestingcan be assessed via dynamic retinoscopy.3o A
shiny bell has been found to be an effective target. If
capable, the patient will be instructed to touch the bell
whileaconsequentialchangein accommodation is moni-
tored. Near acuity measures serve to demonstrate im-
proved visual function with lens application. In addition,
changes in binocular coordination can be influenced by
changes in accommodative function through lens appli-
cation. This interaction is invaluable in understanding
the underlying relationship between accommodation and
convergence. Insight into this balance of systems pro-
vides the awareness of an individual's postural and
14
behavioral acquisition of space.
Refraction
Refractive assessment must be performed on an ongoing
basis in orderforprescriptions to support visual rehabili-
tation. Both delayed and dynamic retinoscopy and the
Mohindra technique are advisable.
31
Typically, a trial
frame refraction is performed, moving back and forth
from one eye to the other and observing a reduction in
spasm as convex lens power is methodically added. All
too often, fluctuations in fixation and accommodation
lead to extreme variability. If necessary, a second ap-
pointment should be scheduled to verify consistency in
prescription. Cycloplegicexaminationmaybeperformed
whenquestionsofspasmand latenthyperopicconditions
persist.
32
Photoretinoscopy should be used when conven-
tional standards are unattainable.
33
Perceptual Assessment
Since patients with secondary visual anomalies often
experience disorganized sensorimotor integration, visual
perception is almost always delayed.
34
.35 Although not
previously demonstrated, it is assumed that individuals
with significant difficulty in binocular, accommodative,
andocularmotorfunction will scorelessthan whatwould
benormallyexpected in somevisual perceptual tests.The
MotorFreeTest ofVisual Perceptionmay illustrate this.
TheGesell Copy test,36 theBeery VisuomotorIntegration
test (VMI),37 the Wold Sentence Copy test,38 the Piaget
Right-Left Awareness test,39 the Birch-Belmont Test of
Auditory Visual Integration,40 theTest ofVisual Percep-
tual Skills(TVPS),41 andtheStandingAngelstest
42
areall
tools for assessing thepatient's level ofperceptual devel-
opment.
METHODS OFVISUALREHABILITATION
Prescribing ofLenses
Guidelines for prescribing are summarized in Table I,
and are exemplified by the case histories below.
6 Practical Optometry 4:1, 1993
Table I Guidelines for prescription
1. Small degrees of convex lens power (less than 1diopter) play
an enormous role in stabilizing accommodative, vergence and
fixational ability. (Case #1)
2. Small degrees of concave or astigmatic lens power (less than
1 diopter) represent accommodative spasm until proven
otherwise. (Case #2)
3. Anisometropia greater than 1 diopter needs to be corrected.
(Case #3)
4. High degrees of refractive error can be partially corrected.
(Case #4)
5. Patients should have full correction when indicated, prior to an
active therapy program. (Case #5)
6. Initial prism correction should not be prescribed unless potential
for fusion is unavailable without it. (Case #6)
7. Prism is best used after lateral fusion is established. (Case #7)
8. Patching procedures should be considered when binocularity is
unavailable. (Case #8)
Case #1. A lO-year-old boy diagnosed with cerebralpalsy
presented with complaints of gravitational insecurity,
distractibility, and inability to sustain fixation and focus
while reading. Because ofhis intensifying frustration, his
motherhadconsultedanumberofoptometristsandophthal-
mologists, who felt thatthere was littleto bedone visually
and that eyeglasses were not warranted. The patient was
subsequently diagnosed with convergence insufficiency,
accommodative dysfunction, ocular motor inefficiency,
and a mild degree of hyperopia. Accommodative lens
treatment was recommended and +0.75D spheres auat
distance,and +1.25Dau at near intwo pairsof glasseswere
prescribed. Immediately, visual acuity improved from 201
40 aD and 20/60 as at distance, to 20/30 and 20/40,
respectively. Nearacuity improvedfrom20/60 aDand201
80 asto20/30 au.Afterafewmonthsoftreatment,acuity
continuedtoimproveto20/25 auatdistanceand20120 au
at near. Thepatient's presenting behavioral symptoms are
subsiding as treatment continues. Thus, small degrees of
convexlenspower1D) playasignificantrolein stabiliz-
ing accommodative, vergence, and fixational ability.43
Case #2. A30-year-oldmale, who had sustainedtraumatic
braininjuryandasubsequentcoma,wasprescribed-0.75D
sphereswithdistanceandnear-yokedprismcorrectiontobe
worn full-time. He was unable to read. Upon examination,
hewasinstructedtostopwearinghiseyeglasses.Aprogram
consisting of monocular accommodative and fixational
therapy,as wellas simultaneousperceptionactivitiesutiliz-
ing a red and green acetate technique, was introduced.
Withinafew months, acuities improved from 20/60 to 201
40atdistanceand from 20/30 to 20120 atnearauwithout
lens correction. Apreviouslydiagnosedconstantexotropia
atnearcurrentlypresentsas intermittent.Thepatientis now
abletoreadandcontinuesto improvethroughtheprogram.
He is currently wearing +0.50 D spheres OU for reading.
This case demonstrates that small degrees of concave or
astigmatic lens power 1 D) represent acconunodative
spasm until proven otherwise.
Case #3. An 8-year-old boy diagnosed with spastic quadli-
piegia, seizure disorder, and scoliosis, was referred because
of behavior involving right-field neglect. The patient would
ignore objects placed within his light visual field. Examina-
tion revealed a prescription of +3.00-4.50XI35 OD, and
+ 1.00 OS. Although his previous ophthalmologist had
found the same prescription, she elected not to prescribe
eyeglasses fearing that it would do more hann than good.
After months of negotiating, the patient's occupational
therapist convinced his mother to try the correction. Imme-
diate improvement was experienced and the right-field
neglect was eliminated. Fixation activities were established
with the assistance of the patient's occupational therapist.
Reevaluation after several months revealed a change in
prescliption measuring +4.00-5.00XI35 OD and +3.50-
2.25X45 OS. With the new correction, a constant alternat-
ing exotropia has become intermittent.
This case demonstrates that anisometropia greater
than 1 D requires correction and also highlights the need
for reevaluation and modification of both lens and treat-
ment as the rehabilitative program progresses.
Case #4. A 9-year-old girl diagnosed with Down's syn-
drome and intermittent alternating esotropic strabismus
was referred because of an inability to wear her eyeglasses.
Behavioral difficulties limited the amount of information
obtained from the examination. However, delayed
retinoscopy and the Mohindra technique were achieved and
demonstrated a prescription of -1.50 OD and -3.50 OS.
Dynamic retinoscopy revealed a net prescription of plano
OD and -2.00 OS. The near correction was prescribed with
the hope that improved attention for near activities would
result. After several months, the patient's mother reported
that her daughter was not only wearing her eyeglasses, but
presented with improved attention and a reduced eye tum.
This case demonstrates that high degrees of refrac-
ti ve error can be partially corrected, thereby restricting
environmental stimulation and reducing distractibility.
Case #5. A 42-year-old male, who had been diagnosed with
multiple sclerosis one-and-a-half years prior, was referred
by an occupational therapist for vision therapy. Since the
patient was being corrected for a compound myopic astig-
matism, he was unable to achieve better than 201200 acuity
with or without his glasses while performing near tasks. A
+2.00D add allowed him to achieve 20/25 acuity with both
his right and left eye, and immediately established his
ability to read. For this patient, therapy consisted of the
correct lens prescription that appropriately suited the task.
This case demonstrates that patients diagnosed with
debilitating conditions which affect accommodative function,
such as multiple sclerosis, should have full plus correc-
tion for near activities before any visual rehabilitation
program begins.
Prescribing Prisms
Primary visual processing is dependent on the stability of
the binocular system.
19
Instability of this system creates
vulnerability in gross, fine, and visual motor develop-
ment.
ls
Both the ability of prisms to create dramatic change
in visual posture and the inherent instability of a rehabili-
tative individual dictate the need for restraint when
introducing prismatic correction. It is my opinion that
prism correction should not be initially prescribed unless
the potential for fusion is unavailable without it. (See
case below.) Furthermore, prismatic lens prescriptions
must be ground into each lens. The use of Fresnel paste-
on lenses is not recommended because of variability
created by movement of the plastic lens peeling, reduced
acuity, and the opportunity for dirt and grit to become
trapped underneath the lens.
Case #6. A 62-year-old male, who had experienced three
cerebral vascular accidents (strokes) since 1986, was left
with a vertical deviation. Surgery in 1988, prism cOlTection,
and botulinum injections demonstrated initial improve-
ment, but ultimately the vertical tropia persisted. An occu-
pational therapist's referral resulted in the prescribing of
lenses: OD +1.50-1.50X90; OS +1.00-1.50X90 with a
+2.25D progressive add, and 7 base down OD split. Initially,
fragile fusion was exhibited, requiring the use of simultane-
ous perception activities through red and green anaglyph
techniques. Ultimately, second- and third-degree fusion
were established. The patient is now wearing 13 base down
OD split with 95% fusion in all meridians of gaze, and is
driving a car, his ultimate goal.
In my opinion, prisms should be added to enhance
preexisting fusion established through vision therapy. It
is assumed that reduced visual adaptation, improved
accommodative facility and amplitude, and an awareness
of binocular coordination tend to increase the reliability
of prism correction necessary to further enhance effec-
tive and efficient primary visual processing. Conse-
quently, lateral fusion enhancement is best performed
prior to a vertical prism correction, if possible. (See case
below.)
Case #7. A 26-year-Old male experienced a traumatic brain
injury in 1990 and was consequently in a coma for two to
three weeks. He was refened by a cerebral palsy centre
because of gross, fine, and visual motor ilifficulties. He was
diagnosed with a 12 prism diopter hyperphoria, and accom-
modative, ocular motor, and binocular dysfunction. Inter-
8 Practical Optometry 4: I, 1993
mittent diplopia as well as an inability to read and ambulate
were presented as primary issues. Treatment began with a
red and green anaglyph technique, with the purpose of
reducing suppression and supporting binocularity. Accom-
modative and fixation training coincided with these binocu-
lar tasks. After four months of treatment, a prescliption of
7 prism diopters base down OD split was given. Not only is
the correction less than the original l2-prism diopters
measured, but binocular function is stable and the patient
now reads and ambulates with a cane.
Patients who have suffered traumatic brain injuries
have a greater need for prism correction than other
rehabilitati ve patients. Diplopia
3
is frequently experi-
enced by this group, whereas suppression is an implied
consequence of binocular dysfunction associated with
other rehabilitative disorders of longer duration.
Some behavioral models of vision have promoted the
use of yoked prism correction."' Although I have seen
minimal improvement with this technique, there are
many in the field who have attributed significant success
to it.
Occlusion
The proposed purpose of occlusion is to improve acuity
so that binocularity will be enhanced through a more
equal use of the two eyes. It is of significant concern,
however, that occlusion may disrupt binocularity more
than it enhances.
The evaluation of the potential benefits of occlusion
is one of the most compelling and significant issues
addressed when initiating a program of optometric reha-
bilitation. Direct, indirect, part- or full-time, binasal,
bitemporal, sector, and partial occlusion through the use
of a frosted lens are currently available options.
The approach used with the patients presented in this
paper is the technique of monocular activity in a binocu-
lar field. Red and green acetate techniques are used so
that one eye is central to the activity while both eyes are
peripheral. In this way the benefits of occlusion are
available without its potentially disruptive effects. How-
ever, there are times when occlusion is warranted.
Case #8. A 41-year-old male sustained traumatic brain
injury in 1988 as a result of a car accident, and subsequently
was in a coma for four to five months. A traumatic right
esotropia was diagnosed and had remained unchanged. The
patient's inability to communicate and concern regarding
the extent of vision available to him were presented as
urgent issues. Optometric evaluation consisted of retinoscopy
at a safe distance, as the patient would hit out at anything
within arm's reach. Observation of the postural position of
his eyes and head assisted in understanding the patient's
visual circumstances. With both eyes open he would rub his
right eye, giving the impression of diplopia. Patching the
right eye during the examination seemed to improve the
accuracy of the retinoscopic reflex by apparently reducing
accommodative spasm. A correction of plano -3.00X180
was observed in the left eye. This was prescribed with a
frosted lens in front of the right eye. When glasses were
dispensed, the patient expressed great relief. His communi-
cation skills have improved, and the patient appears happier
in general.
THE SEQUENCE OF TREATMENT
Initial intervention will be based upon the patient's
ability to discriminate and communicate. The goal of
each task is to coordinate a motor response to a sensory
stimulus."5 Wherever possible, accommodative skills are
initially utilized, thus reinforcing foveal fixation. This
supports discrimination and develops a relationship with
binocularity. Fixation and fusion techniques follow, building
physiological and perceptual bridges proprioceptjvely
linked to feeling and understanding. Whenever possible,
patients are educated regarding physiological expecta-
tions and emotional consequences of each level of aware-
ness attajned.'647
Accommodation is sequenced from monocular to
binocular techniques. Adjustment through plus and mi-
nus lenses is connected with discrimination tasks to
which the patient is capable of relating.
Fixation activities often begin with a white flashlight
task, reinforcing the individual's line of sight with the
target. The demand of the technique can be increased by
reducing the size and increasing the distance of the object
of regard. For individuals who have limitations prohibit-
ing physical manipulation, communication boards and
creative switch controls can be used (Fig. 2).
Binocular skills often begin with anaglyph tech-
niques, which reinforce simultaneous perception. Mo-
nocular activities in a binocular field eliminate disrup-
tion of binocularity while enhancing monocular fixation
and peripheral fusion. Antisuppression techniques such
as red and. green flashlights, red and green checker
Fig, 2 Communication boards with creative switch controls
10 Practical Optometry 4: I, 1993
boards, andBrockpostureboardactivitiesareused. Once
binocularity has been attained, the patient may proceed
to conventional fusion activities.
CONCLUSION
Patients with secondary visual anomalies seekassistance
with varying degrees both of disability and capacity to
overcome obstacles.
Remediation and normalization of visual skills not
only improve overall visual and postural performance,
butalso enhance the patient's capacity to attend to tasks
related to auditory processing and kinesthetic function-
ing.
Patients complete rehabilitative visual treatment not
only with varying degrees ofimprovedfunction, butalso
with the understanding that through their determination
and effort, they have gained a newly learned self-aware-
ness. The ability to support and remediate rehabilitative
situations will not only benefit patients by improving
their functional ability, but will give the optometrist the
opportunity to develop the skills and knowledge neces-
sary to preserve and enhance life.D
Acknowledgements:Thanks to Ellen Ettinger for her
finalreview,andaspecialappreciationtoSharonYaroslowitz
for loving the project.
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