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STRABISMUS DETECTION AND AMBLYOPIA PREVENTION IN PRIMARY CARE
By
Elizabeth Williams, BSN, RN
Intercollegiate College ofNursing
A Manuscript Submitted in Partial Fulfillment of the Requirements for the Degree of
MASTER OF NURSING
EASTERN WASHINGTON UNIVERSITY COLLEGE OF NURSING
Intercollegiate College ofNursing, WSU
Spokane Campus
May, 2003
11
To the Faculty ofEastem Washington University
To members of the committee appointed to examine the Clinical Project ofELIZABETH
A. WILLIAMS find it satisfactory and recommend that it be accepted.
:5~ti4Y0}~
(Chair)
ill
ACKNOWLEDGEMENT
The guidance, assistance and support of Cindy Corbett, Ph.D, Lorna Schumann, Ph.D and
Billie Severtson, Ph.D., Washington State University, Spokane, in preparation of this research
paper is gratefully acknowledged. Sincere appreciation is extended to them for their time and
energy for review and revisions.
IV
STRABISMUS DETECTION AND AMBLYOPIA PREVENTION IN PRIMARY CARE
BY
ELIZABETH WILLIAMS, BSN, RN
Intercollegiate College ofNursing, WSU
MAY, 2003
Abstract
Chair: Lorna Schumann, Ph.D.
Primary care providers are charged with the responsibility of identifying abnormal visual
function when performing scheduled health screening of children. Providers performing
pediatric well-child vision examinations are failing to diagnose 5-10% of children with
amblyopia. Failure to recognize and immediately refer conditions such as amblyopia,
strabismus, and uncorrected refractive errors can permanently jeopardize normal visual
development. These conditions can result in poor academic performance and may progress to
blindness. Because optic nerve development occurs until age 10, rapid diagnosis and treatment
correlates to better outcomes, however, treatment should be pursued at all ages of diagnosis.
Critical screening techniques for primary care providers and indepth information regarding
referral and treatment options for clinicians and patients are reviewed.
v
TABLE OF CONTENTS
Page
SIGNATURE PAGE
ii
ACKNOWLEDGMENT
iii
ABSTRACT
iv
TABLE OF CONTENTS
v
LIST OF TABLES
vi
Introduction
1
Statement of Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
Fram.ework and Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2
Etiology and Pathophysiology of Amblyopia
4
History
5
Exam.
6
Review of Selected Research Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8
Synthesis of Research Findings
19
Management
20
Parental Information
22
Su.tnmary' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 24
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25
VI
LIST OF TABLES
Page
Definition of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29
Definition of Visual Testing Terms
30
Office Equipment for Vision Examination
33
Pediatric Eye Exanl Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34
Pediatric Vision Testing Procedures To Detect Strabismus
Screening and Referral Recommendations
35
. . . . . . . . . . . . . . . . . . . . . . . . . .. 37
Chronic Care Model
A
Pediatric Vision Screening Documentation Form
B
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STRABISMUS DETECTION AND AMBLYOPIA PREVENTION IN PRIMARY CARE
Introduction
The Department of Health and Human Services states in Healthy People 2010, that
"vision affects development, learning, communicating, working, health and quality of life" (p
28-3). Improving the visual health of the nation through prevention, early detection, treatment
and rehabilitation is currently a national priority (Healthy People, 2010). The 1994 National
Health Interview Survey reported that 1% of the population under the age of 18 in the United
States are visually impaired (Viisola, 2000). Visual impairment is defined as blindness in one
or both eyes or trouble seeing even with glasses (Viisola, 2000). Strabismus, a misalignment
of the eyes, is the most common eye condition found and occurs in 1 to 4% of the population
(Viisola, 2000). Amblyopia, reduced visual acuity that develops as a result of strabismus, can
cause in blindness and affects 1 to 2% of children (Viisola, 2000.) Early detection and
treatment of strabismus in infancy and early childhood is critical for amblyopia prevention and
vision loss because better outcomes occur when treatment is initiated before optic nerve
development is completed at age 10. Children continue to go blind each year due to lack of
screening by primary care providers and parents who fail to access services. Primary care
providers playa critical role in achieving improvement in the visual health of the nation
through early detection of strabismus and referral to ophthalmology or optometry for
treatment. The purpose of this paper is to enhance primary care providers' ability to detect
strabismus and amblyopia and facilitate parental access to immediate treatment. A definition of
terms related to visual problems are found in table 1.
2
Framework and Theory
The conceptual framework for this study was based on the Chronic Care Model (CCM)
developed by Dr. Ed Wagner, M.D., M.P.H., national director of the Improving Chronic
Illness Care (ICIC) program. The model was revised by a panel of national experts during a
subsequent project, supported by the Robert Wood Johnson Foundation, for use in evaluating
innovative programs recommended by experts. ICIC, based at Group Health Cooperative in
Seattle Washington, is located at the Macoll Institute for Healthcare Innovation. The Chronic
Care Model identifies elements of the health care system, individual provider issues and patient
characteristics that create barriers and result in poor health care outcomes. These elements
address: primary care providers who fail to provide thorough care because they are unable to
follow established care guidelines due to time constraints, providers who provide fragmented
care due to a lack of coordination with specialties, and patients who are not empowered to self
manage their disease. The purpose of the model is to direct focus on system components to
facilitate productive interactions between patients who take an active part in their care and
providers who have the expertise and resources available to provide high quality care (Wagner,
1998).
The Chronic Care Mode~ found in Appendix A, is multidimensional, separating the
"community" and "health system" as the two major overlapping entities. Positioned below
community and health system in a support location are the four essential elements of the health
system. The elements are self management support, delivery system design, decision support
and clinical information systems. The community and health system components all contribute
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to expedite productive interactions between the patient and the provider or practice team
located below the community and health care system (Hyatt, 2001).
Community programs are valuable resources that, when identified, can provide evidence
based programs in partnership with the primary care provider or health care system. Support
from community programs improves patient outcomes, by enhancing the ability of the provider
to detect, and manage specific medical conditions. Primary care providers or health care
systems that work within the Chronic Care Model facilitate this interaction and work in tandem
with the community (Wagner, 1998).
Individual provider issues, when working within a chronic care model, are addressed by
focusing on the health care system components of self-management, delivery system design,
decision support and clinical information systems. The primary care provider is taught that to
achieve self-management support, the provider should educate the patient about how to take
better care of themselves to minimize complications, symptoms or disabilities. The provider
should emphasize that the patient and their parents have the central role in managing their
condition. Information and interventions to enhance confidence are provided to patients and
their families to achieve this goal and ongoing collaborative support is made available. The
delivery system design that is desired is preventive. The provider is taught to be focused on
keeping a patient, as healthy as possible instead of reacting when the patient is sick (Wagner,
1998).
To achieve decision support, the provider is taught that treatment decisions need to be
based on explicit, proven guidelines supported by at least one defining study. Providers must
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be exposed to current research findings and participate in continuing education. The provider
should discuss guidelines with patients or patients' parents so they can make informed
treatment decisions. The primary care provider must remain interactive with specialists when
joint consultation is necessary. Clinical information systems assist the provider with tracking
individual patients, as well as populations of patients. The provider can utilize the system to
ensure that patients comply with recommended guidelines for screening and follow up exam
resulting in better outcomes (Wagner, 1998).
The Chronic Care Model provides a framework that facilitates the use of community
resources, educates providers to enlphasize patient self-management, practice to prevent rather
than react to illness, use of evidence based guidelines to manage conditions and the use of
clinical information systems to improve patient monitoring. Utilizing the Chronic Care Model
can improves communication between the patient and families and the practice team and
results in superior clinical and functional outcomes in children with strabismus and amblyopia
(Wagner, 1998).
Etiology and Pathophysiology ofAmblyopia
The normal visual pathway is developed by the age of2 to 3 months. To focus a visual
image on the retina, all rays of light converge on the macula and retinal area. Images become
sharply delineated. The ciliary bodies accomplish accommodation by contracting which allows
the lens to increase in curvature and to increase refraction of light rays from near objects. This
ocular convergence allows a binocular image to be maintained (Broderick, 1998).
Binocular fusion is achieved by the brain. Each eye, while moving in unison, focuses the
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retinal image on its macula and the brain fuses the image into one. If one eye has a distorted
image on the retina, the brain suppresses the poor image to allow for clear vision. If
suppression occurs, neurological development is interrupted causing visual impairment in the
suppressed eye. (Broderick, 1998).
There are three types of amblyopia; strabismic, refractive and deprivation. Strabismic
amblyopia occurs in the presence of esotropia, exotropia, hypertropia or hypotropia. The
visual axis misaligns the image on the retina and prevents binocular fusion. Refractive
amblyopia occurs when both eyes have significantly different refractive scores. The eye that is
unable to focus the image on the retina is suppressed. If both eyes lack focus, they may both
become amblyopic. Deprivation amblyopia occurs when vision is never allowed to develop
because the retina does not receive a clear image. Deprivation amblyopia can be the result of
unilateral or bilateral congenital cataracts, corneal or vitreous opacity, severe ptosis or
excessive patching (Kaw & Simon, 2001). Suppression over time results in monocular vision,
eliminating peripheral vision and depth perception.
History
Primary care providers playa critical role in the detection of amblyopia, strabismus, and
other visual disorders. A careful visual history and evaluation should be included in all well
child examinations. The academy of ophthalmology and optometry recommend vision
screening at the ages of newborn to 3 months, 6 months to 1 year, 3 years and 5 years
(National Guidelines Clearinghouse, 1997). Comprehensive vision screening should include
collecting information about the following: presenting problem or chief complaint, family
6
history of vision or eye problems, maternal and neonatal conditions that place the child at high
risk for visual disorders, any parental concerns or school reports of visual abnormalities,
worsening grades, poor school performance, ocular history of the patient, and dates of
previous ophthalmologist or optometry examination (National Guideline Clearinghouse, 1997).
Exam
Primary care providers should complete a comprehensive visual examination of all
children and have the ability to detect abnornw findings so that appropriate treatment referrals
can be made. Table 2 lists equipment needed to perform a complete visual exam. The
American Academy of Pediatrics has published pediatric vision screening guidelines that
recommend the use of Snellen letters and numbers, tumbling E charts, picture tests and Allen
figures to test distance acuity in children (Broderick, 1998). In addition, letter charts made up
using the letters H, 0, T, V called HOTV charts, Leah Hyvarinen symbols, sterogram cards,
Randot cards and Ishihara cards should be available to facilitate examination of children at
various developmental stages. These tests are defined in table 3. Visual acuity at 14 feet and
20 feet, color vision results, and stereogram results should be obtained by age 3. Stereogram
results are obtained with the child wearing three dimensional glasses and viewing stereogram
cards such as the standard stereofly. Photoscreening using a camera or video system that
documents images of the pupillary reflexes and bilateral red reflex can be utilized to confirm
vision examination findings in young patients. Photoscreeening assists in making the
determination to refer for amblyogenic factors, such as strabismus, medial opacities and
significant refractive errors in one or both eyes. History information, visual acuity, color
7
vision, and stereogram testing could initially be obtained by office personnel checking patients
in and then reviewed by the primary care provider during the exam portion of the visit.
The visual exam at every age in the primary care office should include the four
components listed in table 4: External inspection, penlight inspection, procedural testing and
fundoscopic exam. The ability to perform certain procedures varies with age. All infants by
the age of 6 months should be examined for fixation preference, ocular alignment and the
presence of any eye disease (DeAngelis, Feigin, Oski & Warshaw, 1999). To assess vision in
an infant, shine a bright light into the eyes, blinking indicates the infant can see. A second
method is to move an object quickly towards the infant, extension of the head will occur if the
infant can see. To assess for fixation preference hold the baby upright grasping the axilla with
your hands and fixing the head with your thumbs. Then, extend your arms and rotate yourself
with the baby slowly in one direction. The baby's eyes will open providing a clear view of the
sclera, iris and extraocular movements. The eyes should look in the direction you are tlrrning
and opposite direction when rotation stops (Bickley & Hoekelman, 2000). Visual acuity,
stereopsis, color testing and strabismus procedures should begin by age 3. Allen or SheridanGardner cards can be used in young or illiterate children when testing for visual acuity.
Stereogram testing using the stereofly cards should be initiated early but no later than age 3 to
assess for binocularity. The Snellen acuity charts can be used for older children or those
children that can use the alphabet (DeAngelis, Feigin, Oski & Warshaw, 1991). Specific
pediatric vision testing procedures to detect amblyopia or strabismus are explained in table 5
and should be consistently performed, as early as possible, but no later than age 3. Abnormal
8
findings can be identified when performing the Hirschberg test, cover-uncover, pupillary
checks and ophthalmic examination. Asymmetry, an uneven finding during testing is the
hallmark symptom that should trigger concern. Specific abnormal findings requiring referral to
ophthalmology or optometry are identified in table 6. Children with strabismus or any obvious
ocular problem should immediately be seen by an ophthalmologist or optometrist (DeAngelis,
Feigin, Oski & Warshaw, 1999). The vision screening form in Appendix B can be utilized to
document exam findings.
Review ofthe Literature
A literature search of peer reviewed research articles was performed using the following
keywords: Amblyopia, strabismus, and pediatric vision. Medline and CINAHL databases
were searched from 1998 to 2003, Pubmed and Medscape databases were searched from 2000
to 2003 and additional references were identified from bibliographies. Research about
amblyopia is limited and does not address the statistical occurrence of misdiagnosis of
strabismus and amblyopia by primary care providers. Ophthalmology and Optometry
disciplines each manage strabismus and amblyopia differently, however, there are very limited
studies that address outcomes in relation to achieving acuity, binocularity and peripheral vision.
Many providers utilize combinations of physical therapy, occupational therapy, chiropractic
care or corneal refraction therapy to address conditions associated with strabismus and
amblyopia but research has not documented a correlation between the benefit of these
therapies and improved outcomes. Available research is critiqued below.
Anderton et aI., (2002) using a descriptive survey design sent out questionnaires to 400
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optometrists practicing in New South Wales to investigate methods used in examining
pediatric optometry patients and the management of amblyogenic conditions. The
questionnaire was constructed following published research guidelines and piloted on 10
optometrists. The instrument consisted of 17 questions in three divided sections: section A,
addressed professional qualifications and practice type, section B, dealt with methods of
pediatric visual assessment and section C, addressed the management of strabismus. The
questionnaire asked respondents to identify the following methods used for visual acuity
measurement and refraction: Leah symbols, Ffookes cube, Preferential looking cards (Teller,
Cardiff), Sheridan-Gardiner test, Tumbling E, Landolt C, Broken wheel test, Sjogrens hand
test, Snellen chart, autorefractor, retinoscopy (cycloplegic or near fixation). Explanations of
these tests are provided in table 2. Respondents were also asked to identify whether they
tested monocular acuities and binocular acuities and to indicate the methods used for binocular
vision assessment, specifically, ocular motility, cover test, stereopsis, near point convergence,
phoria measurement, fusional reserves, accomodative facility and or suppression tests. Finally,
respondents were asked if they performed direct ophthalmoscopy, binocular indirect
ophthalmoscopy, visual field testing, contrast sensitivity, color vision and or electrophysiology
to test visual fimction and ocular health. Ofthe 400 questionnaires sent out to optometrists,
179 (45%) were returned. The data collected from the questionnaire was extrapolated into the
statistical frequency at which respondents performed specific exam procedures and a
comparison was made between children under the age of 4 and children 4 to 8 years old.
Reliability and validity of the tool were not cited in this study (Anderton et aI., 2002).
10
Survey results indicated that none of the respondents had taken postgraduate courses or
obtained specialty qualifications in pediatric optometry or visual development. The
respondents identified that 2% of their patients were under 4 years of age and 10% were in the
4 to 8 year age group. The population estimates for New South Wales, indicated that 5% of
the population is lmder 4 and 5% of the population is aged 4 to 8. Most of the respondents
indicated that they did not use tests specifically designed for pediatric visual acuity assessment.
Monocular acuity, a critical assessment used to diagnose unilateral strabismus or amblyopia
was not evaluated by 15% ofthe respondents in children aged less than 4 and not evaluated by
1% ofthe respondents in children aged 4 to 8. However, for patients in both age groups,
binocular visual function was assessed by ocular motility 94% of the time, cover testing 96%
of the time, stereopsis testing 73% of the time, and a measure of near point convergence 80%
ofthe time. Most respondents reported that amblyogenic factors such as strabismus must be
detected before the age of eight for treatment to be most effective. They reported that they
would not delay treatment and would use refractive correction, occlusive therapy, prism
therapy or refer to another provider for care. Respondents were asked for their comments and
observations about pediatric visual assessment, but the Slunmary of findings did not document
any opinions regarding specific recommendations for screening (Anderton et aI., 2002).
The study findings are limited by the use of a questionnaire without documented reliability
and validity. Although the questionnaire tool was trialed by optometrists, revisions were not
cited. The findings cannot be generalized as a convenience sample was utilized with all
optometrists located from within the same geographic area who were without specialized
11
training in pediatrics. However, the study did yield a 45% response rate which is valid for
analysis.
Study findings are important because the information indicates that primary care providers
may have the opportunity to screen many children under the age of 8 who are not screened by
an optometrist. Study findings also indicate that exam procedures and techniques among
optometrists vary and this lack of standardization may result in a failure to detect strabismus or
amblyopia. Therefore, primary care providers need to continue to be vigilant for amblyogenic
risk factors despite previous examination by optometry. Optometry respondents did not
believe deferment of treatment to be beneficial for children and usually included ophthalmology
as a co-manager when strabismus is diagnosed (Anderton et al., 2002).
Many areas of the nation have instituted 100% screening programs to improve strabismus
and amblyopia detection. The "See to Learn" program sponsored by the Kansas Optometry
Association allows every three year old to be assessed for free by optometry specialists
(Kansas Vision Developmental Center, 2003). Primary care providers should anticipate an
ophthalmology referral rate of approximately 8% of their caseload and should educate all
parents regarding the benefits of obtaining a comprehensive exam by the age of 3 (Azari,
Bertakis, Callahan & Robbins, 2001).
Preschool vision screening programs have been studied to determine how well strabismus
and refractive errors are detected when trained public health nurses administer tests of visual
acuity, stereoacuity and ocular alignment. Bobier, Bryant, Martin, & Robinson (1999) studied
3,434 children over a 3 year period and found that 28.9% of children failed the vision screening
12
in year one, 34.7% failed in year 2 and 25.5% failed in year 3. Vision screening tests were
conducted by 9 different public health nurses who targeted all children registered for
kindergarten. The public health nurses were trained yearly to conduct visual acuity and ocular
alignment. During the second year of screening steroacuity testing was added. If the child
failed a component of the screening they were referred to an eye care practitioner of their
choice. Children who were unable to complete the screening were also referred to an eye care
practitioner. For each child that failed the exam the nlll'Se referred the next child in line that
passed the exam as a control. The eye care practitioners were then required to file reports that
described the major results of their examination. Personnel from the county health unit
compared each practitioner's report to the screening result.
Data from both sources were entered into a computer data base and compared. What
constituted a "visual problem" was defined as the presence of any strabismus, anisometropia, a
difference of 1 diopter or more of refractive error between the eyes, hyperopia of2 diopters or
more in either eye, myopia of one diopter or more in either eye and astigmatism of more than 1
diopter in either eye. During the three year study, 118 children passed the screening by the
public health nurse, but had vision problems as defined above and identified by examination of
the control group by the eye care practitioner. During year 2 of the study, stereoacuity
assessment was added to the screening procedure and the number of children who passed the
public health screening with vision problems decreased. Sensitivity of visual acuity plus
Hirschberg testing in year 1 was 69.9%, in year 2 with stereoacuity 70.9% and year 3, 60.4%.
Specificity testing in year 1 was 75.6%, in year 2 with stereoacuity 69.6% and year 3, 79.7%
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(Bobier et aI., 1999).
The study findings cannot be generalized to the public as a convenience sample was
utilized with analysis of children from the same geographic area. A standardized definition of
"visual disorder" strengthens validity. The sensitivity and specificity findings are weakened
since the number of controls referred was never equal to the nurrlber of screening failures
referred. Strength in the results can be found in the sample size of3,434 children with a mean
age of 51 to 54 months (Bobier et aI., 1999).
The study results indicate that providers are failing to detect vision problems before
kindergarten due to the poor quality of screening procedures or parental failure to access
examination for their child. The study also demonstrates that quality visual examinations can
improve the rate of strabismus and amblyopia detection. Stereoacuity testing appears to playa
very important role in improving this detection (Bobier et aI., 1999)
Vision screening, although critical, is difficult in the preschool population because of
developmental norms such as failure to follow directions, inability to fixate for a prolonged
period of time, and refusal to cooperate with the examiner. Past randomized surveys of vision
screening practices among pediatricians in Illinois revealed that comprehensive vision
examinations of children are difficult to perform due to "inadequate time" and "children too
young" (Berry et aI., 2001). Photoscreening devices have been developed to improve vision
screening in children. Photoscreening instruments are noninvasive devices that can detect
refractive errors, cataracts, medial opacities and misalignment ofthe eyes, but require minimal
cooperation from the child.
14
Berry et aI's., (2001) study compared the use ofa photoscreening device in a total of 51
preschool children (experimental group) against ophthalmic examination (control group). The
children had developmental delays, behavioral problems or medical problems. Every preschool
child in the study was photoscreened and then given a complete ophthalmic examination.
Children. were photoscreened using the instructions in the manual that accompanies the MTI
photoscreener. The lights in the exam room were reduced so that the subject's face was barely
visible. Using the aiming lights, the camera was aimed at a spot in the center of the forehead
and 1.25 inches above the center of the pupils. The subject's attention was then captured by
activation of fixation lights or sound. Once alignment and fixation was obtained the shutter
was triggered. The process was repeated after the flash recharged for a second photograph.
The criteria for photographic quality was symmetric pupil size, appropriate camera fixation,
symmetric corneal reflections and a good view of both eyes and cornea. Pictures were retaken,
immediately, ifreview of the photograph did not meet the specified criteria. Eye photos were
examined, coded and interpreted by a registered nurse who did not have knowledge of medical
record or previous examination findings.
A pediatric ophthalmologist, then performed a complete eye examination consisting of
Snellen or Allen optotype recognition, Teller visual acuity, or assessment of fixation reflex,
measurement of ocular alignment both distance and near, cover/uncover testing, and evaluation
of pupils. These procedures are defined in table's 2 and 5.
The photoscreening and ophthalmology examination findings were entered into a
computer data base and interpreted using a standardized measuring tool with four categories.
15
Category A listed failure of both vision screening and ophthalmology evaluation as a true
positive, category B listed failed vision screening and passed ophthalmology evaluation as a
false positive, category C listed passed vision screening, but failed ophthalmology evaluation as
a false negative, category D listed passed vision screening and ophthalmology evaluation as a
true negative. Sensitivity is the probability that the screening test will be positive when an
abnormality is present. Specificity is the probability that the screening test will be negative
when an abnormality is not present. When compared to complete ophthalmic examination, the
Medical Technology Incorporated photoscreener was found to have a sensitivity of 83% and
specificity of 68% (Berry et aI., 2001). The study findings were limited by the use of a
convenience sample. Additional studies with larger sample sizes need to be pursued to
examine if interventions such as additional technician training or repeat photographs of
abnormal findings can improve sensitivity and specificity. Also, the sample selection which
targeted non verba~ uncooperative and developmentally delayed children may have impacted
sensitivity and specificity. The use of photoscreening devices in an office setting can be an
important tool to stimulate learning and reinforce the ability of the primary care provider to
adequately screen patients for strabismus (Berry et aI., 2001).
A randomized, controlled trial study by Harrod, Harvey, Northstone, Sparrow and
Williams (2002) investigates whether early treatment of amblyopia is more effective when
initiated at younger ages. The convenience sample of3,490 children were born to parents
during the last 6 months of a previous longitudinal study of parents and their siblings in Avon,
England. This study compares a group of children who received intensive orthoptic screening
16
at ages 8,12, 18,25,31 and 37 months with a group of children who receive orthoptic
screening at age 37 months only. Prevalence of amblyopia and visual acuity in the worse
seeing eye was analyzed at 7.5 years of age in this longitudinal study. All 3,490 children were
invited to attend the final examination; however only 1,929 arrived, of which 15 were excluded
based on developmental delay or organic ocular pathology. The parents of the 1,914 children
examined at 7.5 years completed a questionnaire that addressed specifics regarding previous
ophthalmic treatment with eye patching.
Random assignment of3,490 children into a control or intensive group was performed.
Children were allocated into different arms ofthe study according to the last digit in the
mother's date of birth. The intensive group was chosen using the numbers 1, 3, and 5 the
control group was chosen using the numbers 2 and 4. The numbers from 6 through 9 were not
utilized for the randomization process. The orthoptists did not know the mother's dates of
birth or how the allocation was carried out (Harrod et aI., 2002).
The results ofthe study documented that the prevalence of amblyopia was 1.5% in the
intensive group and 2.7% in the control group at the age of7.5 years. Prevalence rates at ages
8,12, 18,25,31 and 37 months were not reported. Residual amblyopia, despite treatment,
was more prevalent in the control group (10/40) than the intensive group (3/40). Visual acuity
in the amblyopic eye was significantly better for treated children in the intensive group with a
mean acuity of 0.15 LogMAR (Log of the Minimum Angle of Resolution) units, than in the
control group with a mean acuity of 0.26 LogMAR units. The LogMAR is used to determine
the geometric mean of the Snellen values. This is necessary because visual acuity chart lines
17
progress in size on a logarithmic scale. Using the arithmetic mean of the decimal Snellen value
can overestimate the visual acuity mean line on the chart. The LogMAR value is calculated as
-Log(Decimal Acuity). Children screened early can see an average of one line more with their
amblyopic eye than children screened at 37 months after treatment. More children in the
intensive group (19/40) received eye patching treatment before the age of3 than in the control
group (5/40). The study suggests that early treatment is more effective than later treatment for
amblyopia (Harrod et aI., 2002).
Study limitations include a lack of documented reliability and validity in regards to
orthoptic examinations and treatment. The questionnaire has no documented reliability and
validity. Generalizability to the general public was strengthened by the randomized, controlled
study design and large sample size.
The Borja et aI., (2002) study analyzed information obtained by questionnaire from a
previous national surveillance study performed for 24 months from July, 1997 to July, 1999.
All ophthalmologists in the United Kingdom were asked to complete a questionnaire on every
patient who had unilateral amblyopia and a corrected acuity of worse than 6/12 in the
amblyopic eye, or newly acquired loss of vision in the nonamblyopic eye for any reason
resulting in acuity worse than 6/12 or visual field impairment that restricted driving. Visual
field impairment specifications were not addressed for those subjects aged 16 years or less.
The questionnaire required the ophthalmologist to report detailed information about
demographics, diagnosis, the date and context of how the vision loss in the nonamblyopic eye
was detected, the level of visual function, the cause of vision loss in the nonamblyopic eye and
18
past and present management. Over a 24 month period, 370 cases were identified. One year
after the initial report was completed the surveillance team sent a second questionnaire to the
ophthalmologist requesting information on changes in visual functions, management, and
outcomes such as employment status. This study extrapolated and analyzed information about
254 of the 370 subjects, aged 11 years or older, who were without any other disorder affecting
their amblyopic eye.
This study calculated the improvement in acuity in the amblyopic eye one year after initial
presentation of symptoms. The Snellen classification was used for analysis. A gain of two
lines or more of Snellen acuity was defined as a clinically significant improvement. Increased
acuity in the amblyopic eye was reported in 19% of people and worsening acuity in the
amblyopic eye was reported in 8% of people. Several factors were found to be associated with
this subsequent improvement in the amblyopic eye. The greater severity of visual loss in the
nonamblyopic eye, and the younger the age at presentation of amblyopia, together with better
previous acuity in the amblyopic eye and new optical treatment all correlated to higher rates of
improvement in the amblyopic eye, despite worsening acuity in the nonamblyopic eye. Study
results indicated that amblyopia can be improved in patients after the age of 11 (Borja et al.,
2002).
Study findings were limited by vague information about the questionnaire and failure to
identify reliability and validity information. Univariate and multivariate statistical analysis were
provided for each predictive factor to substantiate associations with acuity outcomes in the
amblyopic eye. The study utilized a convenience sanlple, which limits the ability to generalize
19
findings to the public. However, it is significant that this specialized population was reported
to have improvement in visual acuity in the amblyogenic eye after age 11. Optic nerve
development is thought to be complete by age 10. The study findings demonstrate the need for
primary care providers to refer all children, regardless of age for treatment of strabismus and
amblyopia.
Synthesis ofResearch Findings
Anderton et aI., (2002) identified a lack of consistency in exam procedures among
optometrist in New South Wales and estimated that optometrists were seeing approximately
50% of children aged 4 years or younger during the critical time point for strabismus and
atrlblyopia detection. Bobier, Bryant, Martin & Robinson (1999) found that approximately
25% of kindergarten children failed vision screening performed by trained public health nurses
and that stereoacuity testing significantly improved the sensitivity of the testing. These study
findings suggest that vision examinations performed by some providers lack the components
required to provide adequate detection of amblyopia and strabismus. The chronic care model
calls for a delivery system design that emphasizes keeping patients healthy rather than
responding to illness and the use of community screening programs when available.
Standardized examination guidelines based on current research findings need to be developed
and utilized. Primary care providers should interact closely with optometrists and
ophthalmologists to ensure quality examinations and management of strabismus and amblyopia.
Harrod, Harvey, Northstone, Sparrow and Williams (2002) found that children screened
20
and treated for strabismus and amblyopia at multiple time points before the age of 37 months
can see better than children who are screened after 37 months. Borja et aI., (2002) found that
visual acuity improvement occurs in patients over the age of 11 with treatment. The Chronic
Care Model encourages primary care providers to remain educated about current research
findings, which suggest intensive screening for amblyopia and strabismus should occur before
the age of3 to ensure the best outcomes. However, referral should be made for amblyopia and
strabismus treatment in patients at all ages to ensure that the patient maintains the maximal
functional level.
Management
Evidenced based guidelines should be written to guide the primary care provider through
action steps designed to improve the detection and management of strabismus and amblyopia.
A review of literature is necessary to understand which treatment options result in the best
outcomes. Treatment for strabismus will improve the prognosis for achieving visual function
and good cosmetic results. The first goal of treatment for strabismus is to obtain good visual
acuity in each eye. The treatment usually prescribed is correction of the refractive error
followed by patching of the good eye to stimulate optic nerve development in the suppressed
eye. Occlusion therapy is continued until the best visual acuity is reached. The second goal of
treatment is correction of the strabismus. Miotic therapy, corrective lenses, orthoptics vision
therapy and or surgery are all utilized to achieve this correction. Vision therapy is provided by
developmental optometrists who are board certified in the diagnosis and treatment of
children's visual disorders. Surgery on the extraocular muscles is performed by an
21
ophthalmologist-(Gellis & Kagan, 2002). The chronic care model encourages the provider to
maintain a close interaction with all specialists involved in the care. A team approach to care is
essential because complex treatment options may need to be explained to the patient and or
parents to ensure that self management decisions will result in good outcomes.
A retrospective review of records performed by FitzGerald and Krumholtz (1999)
investigated outcomes related to treatment modalities in patients diagnosed with refractive
amblyopia. A protocol for treatment of refractive amblyopia was developed and distributed to
all pediatric clinical doctors within the State College of Optometry. The clinical setting
consisted of students with supervising clinicians who verified all findings. The guidelines
required an exam visit 4 to 6 weeks after initial diagnosis and again in 2 to 4 months. Visual
acuity and binocular testing were required at every visit. For a period of 6 months, all pediatric
patients with a new diagnosis of unilateral refractive amblyopia were retrieved and the patient
was then tracked for 6 months from diagnosis. The olitcome analysis was limited to two areas:
visual acuity and stereopsis. Improvement was defined as an increase of at least 20 seconds of
arc on the stereopsis test and at least a two line improvement in visual acuity on the Snellen
chart.
The convenience sample obtained was 78, consisting of 44 male slLbjects and 34 female
subjects. There were 3 patients aged 0 to 1 yr 11 months, 24 between the ages of2 and 5
years 11 months, 31 between the ages of 6 and 8 years 11 months, and 20 patients in the 9 to
14 year old category. Four treatment modalities were offered to these patients: no
intervention, optical correction only, or optical correction with a patching regimen and vision
22
therapy. The sample was reduced to 52 patients because 4 patients did not receive any
treatment and 22 subjects did not attend the follow up visit or had erratic attendance for vision
therapy. Optical correction alone was utilized as treatment for 17 patients, optical correction
and occlusion was utilized by 23 patients, and 12 patients received optical correction and or
patching in conjunction with vision therapy. Results are not reported for the 4 patients who
did not receive any treatment (FitzGerald & Krumholtz, 1999).
The study found that optical correction alone increased visual acuity in 41 % of the
subjects and 18% demonstrated an improvement in stereopsis. The optical correction and
patching group demonstrated a 69% improvement in acuity and 30% increase in stereopsis.
The vision therapy group showed a 67% improvement in visual acuity and a 67% increase in
stereopsis. The study results indicate that patching alone can improve visual acuity, but
stereopsis (binocular acuity) is improved at a higher rate when vision therapy is added to the
treatment regimen (FitzGerald & Krumholtz, 1999).
The study findings would have been strengthened with the inclusion of the record data
gathering form from the patient records. Also, the study would be more complete with the
inclusion of the follow up results on the children who chose no treatment. However, validity
was established with the stated definition of improvement in visual acuity and stereopsis. The
findings cannot be generalized to the public, as a convenience sample was utilized and the
sample size was small.
Parental Information
Primary care providers should encourage parents to investigate treatment options for
23
visual disorders. There is a national nonprofit organization established by parents dedicated to
raising public awareness about vision. State chapters can be located by calling 1-800PAVE988; email: [email protected]; or access the internet web page at
www.visiontherapydirectory.com. Amazon.com has many books about the myths of20/20
vision and strabismus and amblyopia.
Vision therapy is usually supervised by the behavioral optometrist, but carried out by a
trained vision therapist. The frequency and length of treatment needs to be discussed. If
parents choose to investigate vision therapy, the primary care provider should advise parents to
obtain the following information from potential vision providers. The frequency and length of
treatment needs to be discussed. The cost and length of sessions should be discussed. How
often does the vision therapist and optometrist conference regarding progress or problems?
Does the office provide the option of home computerized therapy and if so, what is the cost?
To identify health insurance coverage, parents should obtain the diagnosis and ICD 9 from the
provider and contact the company to ask "Do you cover vision therapy services for the
diagnosis of X, ICD 9 code X, for my child who is X years of age. Be aware that age
limitations for the benefit may exist. What is the benefit amount per session? Is a preferred
provider benefit available? What is the plan maximum? Many insurance companies do not
cover vision therapy.
Vision therapy can result in multiple contact lens and eye glass prescription changes.
Parents should be advised to investigate the most inexpensive places to purchase glasses and
contact lenses. Typically, the behavioral optometrist is unable to provide contact fitting
24
services, which should be done on a yearly basis. Disposable contacts may be the most cost
effective.
Summary
The Chronic Care Model emphasizes the benefit of working in partnership with
community entities, such as the "see to learn" program that provides free screening for
strabismus and amblyopia. The primary care provider and the patient both benefit from
utilization ofthese resources. The Chronic Care Model encourages primary care providers to
follow a delivery system design based on detection and prevention as opposed to reactionary
responses to acute conditions. Support for participation in activities that promote expertise in
the performance ofquality history, physical and examination ofthe visual system are necessary
to reduce the incidence of amblyopia. Access to the randomized amblyopia treatment studies
that are currently in progress will be integral to the creation of quality management guidelines.
Coordination with optometry and ophthalmology services is vital because ofthe complexity of
treatment options. Patients and their parents will require extensive information to successfully
self manage the treatment. Primary care providers who recognize the need for comprehensive
vision examination and who refer all children with amblyogenic characteristics to eye
specialists can facilitate change by eliminating amblyopia caused by strabismus. Providers must
recognize that delays in diagnosis and referral can permanently impair visual health. Providers
who are knowledgeable about visual impairments, skilled in detection, and who make referrals
in a timely manner, will improve the visual health ofthe nation.
25
Reference List
American Foundation for Vision Awareness. (2001). A nurse's guide to children's vision and
learning. (1 st ed.). [Brochure]. St. Louis, MO: B. Edwards.
Anderton, P., Kim, H., Kim, J., Lee, M., Suttle, C., & Wong, R. (2003). A survey of
pediatric visual assessment by optometrists in New South Wales. Clinical and
Experimental Optometry, 86, (1), pp. 19-33.
Azari, R., Bertakis, K., Callahan, E., Robbins, J. (2001). Predictors ofpatient referrals by
primary care residents to specialty care clinics. Retrieved April 3, 2003, Fronl
http://www.stfm.org/fmhub/Fullpdf7march01/crm.pdt:
Bane, M & Beauchamp, G. (2001). Update on vision screening. Retrieved March 24, 2003,
From http://www.revophth.com/2001/march01pediatricpatient.htm.
Berry, B., Duthie, M., Flynn, J., Schiffman, J., Siatkowski, R., & Simons, B. (2001).
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27-34.
Bickley, L. & Hoekelman, R. (2000). Physical exam and history taking. (3 rd ed.).
Philadelphia, PA: J.B. Lippincott Co.
Bobier, W., Bryant, L., Martin, E., & Robinson, B. (1999). Measurement ofthe validity of a
preschool vision screening program. American Journal ofPublic Health, 89, (2), pp.
193-198.
Borja, M., Eggitt, I., Logan, S., Rahi, J., Taylor, D., & Timms, C. (2002). Prediction of
improved vision in the amblyopic eye after vision loss in the non-amblyopic eye. The
26
Lancet, 360, 621-622.
Broderick, P. (1998). Pediatric vision screeningfor the family physician. Retrieved March
26, 2003, From http://www.aafp.org/afp/980901ap/broderic.html.
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http://www.qualityschlar.com/TWIV sNA%20HIVN A%20model%20for%20effective%2
O.
DeAngelis, C., Feigin, R., Oski, F., Warshaw, J. (1990). Principles and practice of
pediatrics. (4th ed.). Philadelphia, PA: J.B. Lippincott Company.
Edelman, C. & MandIe, C. (2002). Health promotion throughout the lifespan. (5 th ed.). St.
Louis, MO: Mosby.
Eggitt, I., Logan, S., Rahi, J., Taylor, D., & Timms, C. (2002). Risk, causes, and outcomes of
visual impairment after loss of vision in the non-amblyogenic eye: a population based
study. The Lancet, 360, 597-602.
Krumholtz, I., FitzGerald, D. (1999). Efficacy oftreatment modalities in refractive
amblyopia. Journal ofthe American Optometric Association, 70, (6), pp. 399-404.
Gellis & Kagan. (2002). Current Pediatric therapy. (17th ed.). Philadelphia, PA: W.B.
Saunders.
Halle, C. (2002). Achieve new vision screening objectives. The Nurse Practitioner, 27, (3),
pp. 15-31.
Harrod, R., Harvey, I., Northstone, C., Sparrow, J., & Williams, C. (2002). Amblyopia
treatment outcomes after screening before or at age 3 years: Follow up from randomized
27
trial. BMJ, 324, 1549-1551.
Hyatt, J. (2001). Integrating disease management across multiple disease states. Retrieved
April 8, 2003, From http:www.kpcmi.org/presentations/HO-IntegratingDM-NMHCC82001.pdt:
Kansas Vision Developmental Center. (2003). Children's vision information network: Lazy
eyes. Retrieved February 28, 2003, From http://www.childrensvision.com/lazy_eyes.htm.
Kaw, P. & Simon, J. (2001). Commonly missed diagnoses in the childhood eye examination.
American Family Physician, 64, (4), pp. 623-628.
Mills, M. (1999). The eye in childhood. Retrieved March 21,2000, From
http://www.aafp.org/afp/99090 1ap/907.html.
National Guideline Clearinghouse. (1997). Pediatric eye and vision examinations. Retrieved
August 29, 2002, From
http://www.summary.asp?guideline=OO1211 &summary_type=briet:
National Guideline Clearinghouse. (1997). Pediatric eye evaluations. Retrieved August 29,
2002, From http://www.summary.asp?guideline=000406&summary_type=briet:
Newell, F. (1992). Ophthalmology principles and concepts. (7th ed.). St. Louis, MO: Mosby
Ohio KePRO. (2002). Chronic care model components and change concepts. Retrieved
From
http://www.ohioKeproinc.com/providers/HCQIP/change%20packet%20CD/QualitYOA»20.
U.S. Department of Health and Human Services. (2000). Healthy people 2010. (Conference
Ed.). Washington, DC: Author.
28
Virtual Naval Hospital. (2003). Put prevention into practice: Clinician's handbook of
preventive service, 2nd edition: children and adolescents screening. Retrieved February
28, 2003, From http://www.vnh.org/PreventionPractice/ch11.html.
Viisola, M. (2000). Statistics on children with visual impairments. Retrieved April 3, 2003,
From http:www.lighthouse.org/edstats_2000.pdf.
Wagner, E. (1998). Improving chronic illness care. Retrieved April 8, 2003, From
http:wwwimproving chroniccare.org/change/modeVcomponents.html.
Weber, J. (2000). Nurses' handbook ofhealth assessment. (4th ed.). Philadelphia, PA: J.B.
Lippincott Company.
Wong, D. (1999). Whaley & wong's nursing care ofin/ants and children. (6th ed.). St.
Louis, MO: Mosby.
29
Table 1
Definition ofTerms
Amblyopia
A reduction in vision acuity in one or both
eyes not attributed to structural or
pathological anomalies. It is not correctable
by refractive means and results from a
developmental abnormality of the central
visual pathway.
Binocular Coordination
The ability to use both eyes together.
Stereopsis (Binocular depth perception)
The ability to judge relative distances of
objects and to see and move accurately in
three dimensional space.
Strabismus
A misalignment of the eyes. Four types:
Esotropia, exotropia, hypertropia, hypotropia.
Esotropia
While one eye looks straight ahead, the
misaligned eye looks toward the nose.
Exotropia
While one eye looks straight ahead, the
misaligned eye looks away from the nose.
Hypertropia
While one eye looks straight ahead, the
misaligned looks upward.
Hypotropia
While one eye looks straight ahead, the
misaligned looks downward.
American Foundation for Vision Awareness
30
Table 2
Definition of Visual Testing Terms
Snellen Letters and Number Test.
Square black symbols that uses letters or
numbers of the English alphabet for testing at
20 feet. For testing acuity of distant vision;
The letters vary in size in such a way that each
one sub tends a visual angle of5' at a
particular distance (Whaley & Wong, 1999).
Tumbling E Charts
Square black symbols of the letter E used in
such a way to measures visual acuity in
children. Uses the capitol E pointing in four
directions; children "read" the chart by
showing the direction ofthe letter E or using a
large duplicate E to match the chart E at 20
feet (Whaley & Wong, 1999).
Allen Figure Test
Picture cards of a tree, birthday cake, horse
and rider, telephone, car, house, and teddy
bear used to test visual acuity at 15 feet in
children who cannot read but can recognize
pictures (Whaley & Wong, 1999)..
HOTV Charts
A chart with the letters H, 0, T & V for
testing visual acuity at 10 or 20 feet. The
child names the letters on the chart or matches
them to a demonstration card (Whaley &
Wong, 1999).
Lea Hyvarinen Test
The child identifies figures on a wall chart by
matching the picture in the Lea book. The
Lea book is a spiral bound book of flash cards
of a house, apple circle and square in different
sizes (Whaley & Wong, 1999).
Stereogram Test
A diagram or picture which represents objects
in such a way as to give the impression of
relief of solidity; also a stereograph (Newell,
1992)
31
Randot Test
The Randot tests the ability to identify six
geometric forms from random dot
backgrounds. The figures cannot be identified
without glasses (Newell, 1992)
Ishihara Test
A test for color vision deficiency that utilizes a
series ofpsuedoisochromatic plates on which
numbers or letters are printed in dots of
primary colors surrounded by dots of other
colors; the figures are discernable by
individuals with normal color vision (Newell,
1992)
Preferential Looking Cards (Teller, Cardiff)
Selection of preferential looking pictures
designed to measure acuity in toddlers aged 13 years and in individuals with intellectual
impairment. The calm infant is held in front of
two screens of matching luminance, one
displays a grating pattern, the other displays a
blank field. Infants prefer to look at the
pattern and visual acuity is estimated by the
hidden examiner who estimates the stripe
width seen by the infant (Newell, 1992).
Sheridan-Gardiner Test
A test that uses geometrical shapes, letters or
patterns in decreasing sizes to test visual
acuity in a child who is illiterate or below
reading age. The child and examiner are
spaced 6 meters apart. The child is then asked
to point to identical patterns on a chart held at
reading distance (DeAngelis, Feigin, Oski &
Warshaw, 1990).
Landolt C
The Landolt broken ring is a round black
symbol with a break in the ring that subtends a
1 minute angle and the entire ring subtends a 5
minute angle. It is used to test visual acuity in
preschool children and illiterates. The child
stands 5 meters away and identifies the
location of the gap in the ring; top, left, right,
or bottom. The ring is rotated over multiples
of 45 degrees on the chart. Commonly used
in research studies (Newell, 1992).
32
Broken Wheel Test
An acuity test produced by Bemell
Corporation. The child using his or her finger
points to the broken part on the car (Newell,
1992)
Sjogren Hand Test
A test for visual acuity using isolated hand
charts (Newell, 1992)
Auto Refractor
An instrument that automatically measures the
deviation of rays of light when passing from
one transparent medium into another of
different density (Newell, 1992).
Retinoscopy (Cycloplegic, Near Fixation)
The objective method of determining the
refraction ofthe eye by observing the
movements of the reflection of light from the
eye by means of ophthalmoscope (Newell,
1992).
33
Table 3
Office Equipment For Vision Examination
Tools
Acuity Charts
Miscellaneous
Ophthalmoscope
Snellen letter charts
Polarized glasses - 3
dimensional
Penlight
Numbers charts
Stereogram cards
Adhesive Occluder
Tumbling E chart
Randot cards
Plastic Occluder
Titmus slide letters HOTV
Ishihara color vision cards
Stationary target
Allen Figures
Puppet
Photoscreening Camera
Leah Hyvarinen Symbols
34
Table 4
Pediatric Eye Exam Components
External Inspection
Penlight Inspection
Procedures
Fundoscopic
Exam
Lids
Conjunctiva
Peripheral Vision ck
Red Reflex
Lashes
Sclera
Visual Field ck
Optic Disc
Lacrimal gland
Iris
Accommodation
Retinal Arteries
Tear Duct
Pupillary Response
Alignment
Veins
Orbital protrusion
Cornea
Craniofacial
configuration
Weber, 2000
Arteries
Macula
35
Table 5
Pediatric Vision Testing Procedures to detect Strabismus
Name of Test
Procedure
Peripheral Vision Check
Examiner faces client at a distance of2-3
feet. Client and examiner look directly
ahead and covers the eye directly opposite
each other. Client and examiner should
report seeing object at the same time as it
approaches the periphery.
Visual Field
Examiner asks client to follow an object
as it is moved through the six cardinal
fields of vision. Eyes should move
smoothly throughout the fields. Eye
jerking is abnormal.
Accommodation
Client should be directed to stare at an
object 3-4 feet away. Examiner moves
the object toward's the nose. Pupils
should converge and constrict as object
moves in. Pupil responses should be
uniform.
Alignment. CoverlUncover.
Have the client focus on a stationary
target. The examiner places a hand or
cover in front of one eye and observes the
other eye. The observed eye should not
move and the covered eye should not
move as cover is removed. Movement is
abnormal and demonstrates the presence
of strabismus. If the child moves to avoid
occlusion refer.
36
Pupillary Response
Check direct pupil response by asking the
client to look straight ahead. The
examiner approaches each eye with a
penlight from the client's side.
Illuminated pupils should constrict.
Consensual pupil response is checked by
following the same procedure and noting
if the pupil opposite to the one illuminated
constrictssUnuhaneously.
Corneal Light Reflex
Have the client fixate on a penlight 2 feet
away; shine the light directly in eyes and
observe the light reflection. Displacement
of the light reflex from the center of the
pupil or asymmetry demonstrates
abnormal alignment and indicates
strabismus.
Red Reflex
Darken the room, client should have eyes
open voluntarily. The ophthalmoscope is
held to the examiner's eye and arm's
length from the client's eyes. The red
reflex exam is rated as normal when the
reflections of the two eyes are seen as
equivalent in red-gold color, intensity, and
clarity and there are no opacities or white
spots within the area of either or both the
red reflexes. Lack of red reflex means the
client has a cataract or is blind.
(Virtual Navy, 2003) (Weber, 2000)
37
Table 6
Screening and Referral Recommendations
Age
Screening Method
Newborn to 3 months
Red Reflex
1 month
Indicators Requiring Eva)
I
Abnormal or Asymmetric
Corneal Light Reflex
Asymmetric
Inspection
Structural Abnormality
Fixation
Poor following
Intermittent strabismus
Constant strabismus
Acuity 20/400 to 20/600
Deviation
Horizontal follow to midline
normal alignment
Acuity 20/300
2 months
Vertical following to
midline
normal alignment
6 months to 1 year old
Red Reflex
Abnormal or Asymmetric
Corneal Light Reflex
Asymmetric
Alternate Occlusion
Failure to see object equally
Inspection
Structural Abnormality
Visual Acuity
20/20 to 20/30
Binocularity
well developed
Fix and Follow with each
eye
Failure to fix and follow
Visual Acuity
20/50 or worse or difference
of2lines between eyes
Red Reflex
Abnormal or Asymmetric
Corneal Light Reflex
Asymmetric
CoverlUncover
Ocular RefixationIMovement
3 years old
38
5 years old
Older than 5 years
Stereoacuity
Failure to identify random
dot or Titmus stereogram
Inspection
Structural abnormality
Visual Acuity
20/30 or worse or difference
of2lines between eyes.
Red Reflex
Abnormal or Asymmetric
Corneal Light Reflex
Asymmetric
CoverlUncover
Ocular RefixationIMovement
Stereoacuity
Failure to appreciate random
dot or Titmus stereogram
Inspection
Structural abnormality
Visual acuity
20/30 or worse, or 2 lines of
difference between the eyes
Corneal light reflex
Asymmetric
CoverlUncover
Ocular refixation movement
Steroacuity
Failure to appreciate
steropsis
Red Reflex
Abnormal or asymetric
Inspection
Structural abnormality
American Academy of Ophthalmology, 1997. Virtual Naval Hospital, 2003.
39
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40
I
I
I
I
AppendixB
I
:
Pediatric Vision Screening Documentation Form
:EXAM: Newborn-3 month_ _ 6 month-1 yr _ _ 3 yr_ _ 5 yr _ Yearly after 5 yrs /Age
Ophthalmology/Optometry last exam date
. Date of Referral Optician/Ophthalmologist
_
_
I
:mSTORY:
:Presenting/Parent Concerns:
I
_
Patient Medical Hx
Birth Hx
MatemalHx
Family Ocular Hx
Diabetes
Juvenile RA
Neuro-degenerative dx
Premie 28wks/<
Steroid admn
Oxygen at birth
Rubella
Toxoplasmosis
Herpes/CMVIHIV
Glasses
Strabismus
Ambylopia
Retinoblastoma
Cataract
Glaucoma
SYMPTOM SCREENING:
Fatigue w/reading
Worsening Grades
Poor academic performance
Head tilting
Closing/blocking one eye
Loss of place w/reading
Failure to recognize same word in next sentence
Omits, inserts or rereads letters/words.
Avoidance of near work
Letters/lines run together or jump around
Letter reversals after second grade
Poor eye hand coordination
Jerky eye movement
Eyes Crossed/turned inlout
Squinting
Eye rubbing
Excessive blinking
Tearing w/computer use
Blurred/double vision
Headache
Dizziness
Nausea
VISUAL ACUITY:
Uncorrected: (20 ft)
Corrected: (20 ft)
N ear acuity (14 ft):
Color vision:
I
right eye
right eye
right eye
Normal
left eye
left eye
left eye
Abnormal
INSPECTIoN:
WNL
NE
Lids, Lashes
Lacrimal gland/duct
Orbit (protrusion)
Cranial Facial features
Peripheral vision
Visual Fields (6)
Accommodation
Alignment cover/uncover
PENLIGHT EXAM:
Iris
Sclera
Conjunctiva
Pupil direct & consensual
Corneal light check
FUNDoScoPIc EXAM:
Red Reflex
Optic Disc
Retinal AV Vessels
Macula
()
()
()
()
()
()
()
()
()
()
()
()
()
()
()
()
(
(
(
(
(
)
)
)
)
)
(
(
(
(
(
)
)
)
)
)
(
(
(
(
)
)
)
)
(
(
(
(
)
)
)
)
Norm (Age 3: 20/50, age 5: 20/40, >5: 20/30.)
(Refer if 2 lines difference between eyes)
_
. Stereogram: Normal
Abnormal
EXCEPTION
A: - - - - - - - - - - - - - - P: Referral to Optometry or Ophthalmology