Open Journal of Ophthalmology, 2013, 3, 7-12
http://dx.doi.org/10.4236/ojoph.2013.31003 Published Online February 2013 (http://www.scirp.org/journal/ojoph)
7
Comparison between the PlusoptiX and IScreen
Photoscreeners in Detecting Amblyopic Risk Factors in
Children
Jing Grace Wang1, Donny W. Suh2,3
1Mercy Catholic Medical Center, Philadelphia, USA; 2University of Nebraska Medical Center, Omaha, USA; 3Wolfe Eye Clinic,
West Des Moines, USA.
Received October 1st, 2012; revised November 3rd, 2012; accepted November 10th, 2012
ABSTRACT
Purpose: To compare the accuracy of plusoptiX A08 photoscreener (PPS) and iScreen 3000 photoscreener (IPS) in
objectively screening for amblyopic risk factors in children age 5 months to 13 years old. Methods: Cross-sectional
study of 148 children who received photoscreenings via PPS and IPS and a comprehensive pediatric ophthalmic ex-
amination in our office. Patients were considered to have amblyogenic risk factors based on the AAPOS referral criteria
guidelines. Results: 45 percent of patients undergoing a pediatric ophthalmology examination were found to have am-
blyopia or amblyogenic risk factors. In this study, PPS demonstrated an overall sensitivity of 75.4%, specificity of
68.0%, positive predictive value (PPV) of 67.1%, and negative predictive value (NPV) of 76.1%. However, IPS photo-
screener had an overall sensitivity of 66.2%, specificity of 87.6%, PPV of 81.8%, and NPV of 75.5%. Discussion: The
accuracy of PPS and IPS was compared in different age groups. The sensitivity and specificity were analyzed according
to varied amblyogenic risk factors. The statistic results of this study were compared to those of previous studies, in-
cluding Vision in Preschoolers (VIP) Study and the Iowa PhotoScreening Program. Conclusion: PPS and IPS proved to
be useful tools in the objective vision screening in children. PPS was found to have a higher sensitivity, and IPS showed
a higher specificity and PPV in detecting amblyopic risk factors. In conclusion, one device may be more beneficial over
the other, depending on the patient population and office settings.
Keywords: Amblyogenic Risk Factors; Photoscreeners
1. Introduction
Amblyopia is a major cause of visual problems in the
developed world [1-3] and the leading cause of blindness
in the 20 to 70 year age group [4], affecting 2% to 5% of
the population [5]. Several studies, including the Pro-
spective Amblyopia Treatment Study, have demonstrated
that amblyopia treatment is highly effective when detected
and treated in young children [6-12]. Early detection is
critical, because there is a window for successful treat-
ment [6,7,10]. US Preventive Services Task Force reco-
mmends preschool vision screening, beginning at age 3,
which is consistent with the American Academy of Pe-
diatrics “Recommendations for Preventive Pediatric Health
Care,” and Bright Futures Guidelines for Health Supervi-
sion of Infants C hi l dren and Ad ol escent s [13-15].
Traditional vision screening methods have a relative
low compliance due to high over-referral rates, low sen-
sitivity and low specificity [16]. Newer screening me-
thods, including photoscreeners and autorefractors, have
been proposed as potential replacements or supplements
to traditional screening methods [17-25]. Potential ad-
vantages are reduced testing time, increased objectivity
of screening, and enhance testability rates in younger
children, who may be poorly cooperative with traditional
tests. Potential disadvantages are the high initial costs
associated with the instruments, and the need with some
photoscreeners for external interpretation of screening
results [15].
The purpose of this study is to compare the accuracy
of plusoptiX A08 photoscreeners (PPS) (plusoptiX Inc.,
Hillsboro, Beach, FL) and iScreen 3000 photoscreeners
(IPS) (iScreen Vision, Cordova, TN) in objectively scree-
ning for amblyopic risk factors in children age 5 months
to 13 years old.
2. Methods
We evaluated the PPS and IPS for detecting amblyopia
and amblyogenic risk factors in a pediatric ophthalmolo-

Comparison between the PlusoptiX and IScreen Photoscreeners in Detecting Amblyopic Risk Factors in Children
8
gy practice in Central Iowa on children age 5 months to
13 years. This is a cross-sectional study of one hundred
forty-eight subjects. Before starting this research we re-
ceived Clinical Research Board approval in West Des
Moines, IA. We received a waiver of consent owing to
the low risk nature of this research and followed appro-
priate Health Insurance Portability and Accountability
Act of 1996 guidelines.
After retrospective chart review during a 2 months pe-
riod, all children ages 5 months to 13 years who had a
cycloplegic refraction and photoscreening with PPS and
IPS devices within 6 months were included. One hundred
and forty-eight children were examined consecutively in
our office. Each patient had photoscreenings via PPS and
IPS and a comprehensive pediatric ophthalmic examina-
tion (gold-standard eye examination) during the same
visit. The photoscreening was performed by either a cer-
tified orthoptist or an ophthalmic technician prior to the
patient’s examination.
PPS performs refraction at a 1 meter distance under
non-cycloplegic conditions. The AAPOS criteria apply to
cycloplegic retinoscopy only and therefore should not be
directly imported into the device. PPS results were inter-
preted by the incorporated software. Referral criteria for
the PPS were provided by the manufacturer [26] (Table
1). The software allows for customized criteria on the
basis of the patient’s age. Our study used categories of 5
to 12 months, 12 to 18 months, 18 to 30 months, 30 to 54
months, and 54 to 72 months. For each group there are
referral criteria for 5 distinct measurements, including
anisometropia, astigmatism, myopia, hyperopia, and ani-
socoria. Patients were automatically referred from the
PPS photoscreening if any of these measurements ex-
ceeded our preset values, if both round pupils could not
be seen (such as with crying, thrashing, or visually sig-
nificant ptosis), if the gaze of one eye is eccentric by
more than 10 degrees (suggesting a tropia), or if a read-
ing could not be obtained after two attempts.
IPS takes image at a 1 meter distance under non-cy-
cloplegic conditions. Images and information are sent via
an Ethernet connection to iScreen Vision Central Analy-
sis for an independent clinical review by a trained tech-
nician. A full patient report is returned to the physician
by email in less than 24 hours.
Table 1. Referral criteria for the plusoptiX A08.
Age, mo Anisome-
tropia, D
Astigmatism,
D
Myopia,
D
Hyperopia,
D
Aniso-
coria, mm
5 - 12 >1.25 >2.00 >2.00 >3.25 ≥1
12 - 18 >1.00 >1.50 >1.50 >2.00 ≥1
18 - 30 >1.00 >1.00 >1.25 >2.00 ≥1
30 - 54 >1.00 >1.00 >1.00 >2.00 ≥1
54 - 240 >0.75 >0.75 >1.00 >2.00 ≥1
The results from both screening methods were com-
pared with comprehensive gold-standard examination
findings. Patients were considered to have amblyopia or
amblyogenic risk factors in the comprehensive examina-
tion on the basis of the American Association of Pediat-
ric Ophthalmology and Strabismus (AAPOS) referral
criteria guidelines (Table 2). The complete examination
consisted of manual cycloplegic retinoscopy using cy-
clopentolate hydrochloride 1%, slit lamp examination,
cover test, Krimsky test, alternate prism cover test, sen-
sory testing using Titmus Stereogram, and fixation pat-
tern assessment. A cycloplegic refraction was performed
that same day or within 6 months. Sensitivity, specificity,
positive predictive value and negative predictive value of
the instruments were defined for different age groups.
3. Results
One hundred and forty-eight patients were included in
this study. Each patient had photoscreenings via PPS and
IPS and a comprehensive pediatric ophthalmology ex-
amination (gold-standard eye examination). 67 patients
out of a total of 148 patients (45%) were found to have
amblyopia or amblyogenic risk factors according to
AAPOS guidelines (Table 2). Amblyogenic risk factors
detected in the gold-standard eye examination are shown
in Figure 1. 20 patients failed the gold-standard exam
due to manifest strabismus alone, including 16 esotropia,
2 exotropia and 2 hypertropia. 23 patients failed the
exam due to refractive error alone, including 16 hyper-
opia, 1 myopia and 6 astigmatism. 21 patients failed the
exam due to a combination of 2 risk factors; 15 patients
have hyperopia and strabismus, 1 patient hyperopia and
astigmatism, 3 patients astigmatism and strabismus and 1
patient myopia and strabismus. 3 patients failed the exam
due to ptosis.
In this study, PPS demonstrated an overall sensitivity
of 75.4%, specificity of 68.0%, positive predictive value
(PPV) of 67.1%, and negative predictive value (NPV) of
76.1%. IPS had an overall sensitivity of 66.2%, speci-
ficity of 87.6%, PPV of 81.8%, and NPV of 75.5% (Ta-
bles 3 and 4). The comparison of the present study to
previous studies was listed in Table 5.
Table 2. Amblyogenic risk factors (AAPOS criteria).
Anisometropia (spherical or cylindrical) > 1.50
Any manifest strabismus
Hyperopia > 3.5 D in any meridian
Myopia > 3.0 D in any meridian
Any media opacity > 1 mm in size
Astigmatism > 1.5 D at 90˚ or 180˚ or >1.0 D in oblique axis (>10˚
eccentric to 90˚ or 180˚)
Ptosis ≤ 1 mm margin reflex distance
Visual acuity per age-appropriate standards

Comparison between the PlusoptiX and IScreen Photoscreeners in Detecting Amblyopic Risk Factors in Children 9
Figure 1. Amblyogenic risk factors detected in gold-stan-
dard eye examination.
Table 3. Screening results using plusoptiX A08 and iScreen
3000.
Results from the gold-standard eye exam
Screening test results + for amblyogenic risk − for amblyogenic risk
plusoptiX A08 All
patients
Fail 49 24
pass 16 51
Age 0-3
Fail 24 16
pass 10 37
Age ≥ 4
Fail 25 8
pass 6 14
iScreen 3000 All
patients
Fail 45 10
pass 23 71
Age 0-3
Fail 19 7
pass 15 47
Age ≥ 4
Fail 26 3
pass 8 24
Table 4. Statistic analysis of screening results.
Screening
test
Patient
population
Sensitivity
(%)
Specificity
(%) PPV (%)NPV (%)
plusoptiX overall 75.4 (75.9)68.0 (69.1) 67.1
(67.7) 76.1 (77)
age 0 - 3 70.5 (70.4)69.8 (71.7) 60.0
(59.4)
78.7
(80.5)
age ≥ 4 80.6 63.6 75.870.0
iScreen overall 66.2 (70.5)87.6 (87.8) 81.8
(82.7)
75.5
(78.3)
age 0 - 3 55.9 (63)87.0 (87.2) 73.1
(73.9)
75.8
(80.4)
age ≥ 4 76.5 88.9 90.075.0
(Excluding subjects who are younger than 1 yr).
Table 5. Comparison of the present study to previous stu-
dies.
Screening
test Study, yearSensitivity (%)
Specificity
(%)
PPV
(%)
NPV
(%)
plusoptiX
A08
present study,
2011 75.4 68.0 67.1 76.1
Power
refractor VIP, 200454 90 70 79
plusoptiX
S04
Matta et al.,
2009 98.9 96.1 97.9
iScreen
3000
present study,
2011 37 94 71 79
iScreenVIP, 200437 94 71 79
MTI Matta et al.,
2009 83.6 90.5 94.2
(Note: Power refractor is a previous model of plusoptiX, and MTI is a pre-
vious model of iScreen.)
The accuracy of PPS and IPS was also compared in
different age groups. Both screening methods showed a
better sensitivity in children age 4 years or older com-
pared to 0 - 3 years (80.6% vs. 70.5% with plusoptiX,
and 76.5% vs. 55.9% with iScreen). The specificity for
both screening tests is similar among different age
groups (Table 4). If patients younger than 1 year old
were excluded, the overall sensitivity of IPS improved
from 66.2% to 70.2%, and the sensitivity for younger
than 3 year old improved from 55.9% to 63% (Table 4).
Data was further stratified according to different
amblyogenic risk factors (Table 6). PPS demonstrated a
sensitivity of 40.0% to detect a single condition of ma-
nifest strabismus, and a sensitivity of 81.8% to detect a
single condition of refractive error. With IPS, the sensi-
tivity to detect a single condition of manifest strabismus
or refractive error is 66.7% and 43.5%, respectively. The
sensitivity is 100% for PPS and 90.5% for IPS when
combined conditions exist.
False positive rates were compared in selected milder
conditions (Table 7). Among all the 81 patients who
passed the gold-standard eye exam, 12 patients have in-
termittent strabismus or heterophoria, 15 have mild hy-
peropia, 6 have mild astigmatism and 13 have multiple
conditions. False positive rate for each condition with
PPS and IPS were listed in Table 7.
4. Discussion
We believe that this study is the first report with com-
parison of PPS and IPS. We conducted a retrospective
chart review of 148 patients who received photo- screen-
ings via PPS and IPS and a comprehensive pediatric oph-
thalmic examination during the same visit. Forty five
percent were found to have amblyopia or amblyogenic
risk factors according to AAPOS guidelines. Among the
amblyogenic risk factors detected in our examination,

Comparison between the PlusoptiX and IScreen Photoscreeners in Detecting Amblyopic Risk Factors in Children
10
Table 6. Comparison of sensitivity for different amblyo-
genic risk factors (interpretation for FN results).
Amblyogenic risk factors
(# of patient) PlusoptiX iScreen
Manifest strabismus (21) 40.0% 66.7%
Refractive error (23) 81.8% 43.5%
Combined condition (21) 100% 90.5%
Overall 75.4% 66.2%
Table 7. Comparison of false positive rate for selected con-
ditions (interpretation for FP result and the specificity).
Selected condition
(# of patient) PlusoptiX iScreen
Intermittent strabismus or
heterophoria (12) 16.7% 8.3%
Mild hyperopia (15) 23.1% 13.3%
Mild astigmatism (6) 80.0% 16.7%
Combined condition (13) 66.7% 30.8%
Overall 32.4% 12.5%
(Definition: mild hyperopia ≥ 2.0 D, mild astigmatism ≥ 1.0 at 90˚ or 180˚
or ≥ 0.75 at oblique axis).
hyperopia, esotropia or a combination of both are the
most frequently encountered amblyopic risk factors.
31 studies evaluated the diagnostic accuracy of various
preschool vision screening tests [15]. The Vision in Pre-
schoolers (VIP) study is the largest study so far to di-
rectly compare the diagnostic accuracy of different indi-
vidual screening test, including Power Refractor (previ-
ous model of plusoptiX) and iScreen [24,25]. The statis-
tical analysis result was shown in Table 5. Iowa Photo-
screening Program reported a study with the largest num-
ber of participants (147,809) using MTI PhotoScreener
over a 9-year period [19]. The sensitivity and specificity
of the MTI PhotoScreener was not evaluated in this study,
but was predetermined to have a sensitivity of 81.8% and
a specificity of 90.6% in a previous study [27]. The over-
all PPV is 94.2% for the MTI Photo- Screener over the 9
years of the program. Differences between studies in the
patient populations, prevalence of target diseases, model
of the devices, and screening thresholds applied make it
difficult to reach strong conclusions about how they com-
pare with one another.
In the present study, PPS was found to have a higher
sensitivity, and IPS showed a higher specificity and PPV
in detecting amblyopic risk factors (Tables 4 and 5). The
difference in sensitivity and specificity may be explained
by the differences in the mechanism of these 2 devices.
The IPS consists of an off-axis photorefractor connected
to a laptop computer that binocularly measures refractive
error in one meridian and measures eye alignment. The
refractive error was determined based on the red reflex
images of the eyes. PPS is a binocular autorefractor which
can detect refractive error down to 0.25 D and significant
strabismus.
Evidence on the comparative accuracy of preschool
vision tests in different age groups among children ages 1
to 5 years is limited. Four studies found no clear dif-
ferences in the diagnostic accuracy of various screening
tests in preschool-aged children stratified according to
age [15]. In this study, the accuracy of PPS and IPS pho-
toscreeners was compared in age 0 - 3 years vs. 4 years
or older (Table 4). Both screening methods showed a
better sensitivity in children age 4 years or older, with
more dramatic difference in IPS results. The specificity is
similar in different age groups. This result demonstrated
a higher false negative rate in the 0 - 3 years old age
group, which may be explained by less cooperativeness
in younger patients during the tests. When patients youn-
ger than 1 year old were excluded, the sensitivity of IPS
was improved 7.1% in 0 - 3 year old age group.
Statistical analysis for PPS was not affected by this
exclusion. The results from our study suggest that PPS is
a more sensitive test in comparison to IPS in detecting
amblyogenic risk factors, with more superiority in pa-
tients age 0 - 3 years.
In order to answer the question of why false negative
results exist, we further stratified the data according to
different amblyogenic risk factors (Table 6). PPS de-
monstrated a lower sensitivity to detect manifest stra-
bismus, with a sensitivity of 40.0% compared to 66.7%
in IPS results. However, PPS has a higher sensitivity to
detect refractive error, with a sensitivity of 81.8% com-
pared to 43.5% in IPS results. The sensitivity increased
significantly when combined conditions exist, 100% for
PPS and 90.5% for IPS.
To explain why machines failed some patients who
have milder disease that do not meet the AAPOS referral
criteria, “mild conditions” was defined in Table 7. PPS
had a highest false positive rate (80%) when mild astig-
matism exists. Coexistence of 2 or more mild conditions
causes high false positive rate, 66.7% with PPS and
30.8% with IPS. False positive rate is in a reversed rela-
tionship to specificity. This result suggests that PPS has a
lowest specificity when mild astigmatism or combined
mild conditions exist. Further study with a larger patient
number is needed to confirm the above statement.
5. Conclusion
The PPS and IPS photoscreeners proved to be useful
tools in the objective vision screening in children. PPS
was found to have a higher sensitivity, and IPS showed a
higher specificity and PPV in detecting amblyopic risk
factors. PPS demonstrated a lower sensitivity in detecting
manifest strabismus, and an excellent sensitivity in de-
tecting refractive error. On the contrary, IPS had a higher

Comparison between the PlusoptiX and IScreen Photoscreeners in Detecting Amblyopic Risk Factors in Children 11
sensitivity in detecting manifest strabismus than refract-
tive error. With mild astigmatism or coexistence of 2 or
more mild conditions, PPS showed a higher false positive
rate, i.e., lower specificity. In conclusion, one device may
be more beneficial over the other, depending on the pa-
tient population and office settings. Despite each device
has its own strengths and weaknesses, they both are found
to be very useful tools in the objective vision screening
in children.
REFERENCES
[1] M. I. Ehrlich, R. D. Reinecke and K. Simons, “Preschool
Vision Screening for Amblyopia and Strabismus. Pro-
grams, Methods, Guidelines, 1983,” Survey of Ophthal-
mology, Vol. 28, No. 3, 1983, pp. 145-163.
doi:10.1016/0039-6257(83)90092-9
[2] K. Simons, “Preschool Vision Screening: Rationale, Me-
thodology and Outcome,” Survey of Ophthalmology, Vol.
41, No. 1, 1996, pp. 3-30.
doi:10.1016/S0039-6257(97)81990-X
[3] K. Attebo, P. Mitchell, R. Cumming, W. Smith, N. Jolly
and R. Sparkes, “Prevalence and Causes of Amblyopia in
an Adult Population,” Ophthalmology, Vol. 105, No. 1,
1998, pp. 154-159. doi:10.1016/S0161-6420(98)91862-0
[4] C. Powell and S. R. Hatt, “Vision Screening for Amblyo-
pia in Childhood,” Cochrane Database of Systematic Re-
views, No. 3, 2009, Article ID: CD005020.
[5] J. R. Thompson, G. Woodruff, F. A. Hiscox, N. Strong
and C. Minshull, “The Incidence and Prevalence of Am-
blyopia Detected in Childhood,” Public Health, Vol. 105,
No. 6, 1991, pp. 455-462.
doi:10.1016/S0033-3506(05)80616-X
[6] M. Eibschitz-Tsimhoni, T. Friedman, J. Naor, N. Eib-
schitz and Z. Friedman, “Early Screening for Amblyoge-
nic Risk Factors Lowers the Prevalence and Severity of
Amblyopia,” Journal of AAPOS, Vol. 4, No. 4, 2000, pp.
194-199. doi:10.1067/mpa.2000.105274
[7] J. H. Groenewoud, A. M. Tjiam, V. K. Lantau, W. C.
Hoogeveen, J. T. de Faber, R. E. Juttmann, H. J. de Ko-
ning and H. J. Simonsz,, “Rotterdam AMblyopia Screen-
ing Effectiveness Study: Detection and Causes of Am-
blyopia in a Large Birth Cohort,” Investigative Ophthal-
mology & Visual Science, Vol. 51, No. 7, 2010, pp. 3476-
3484. doi:10.1167/iovs.08-3352
[8] The Pediatric Eye Disease Investigator Group, “A Ran-
domized Trial of Atropine vs. Patching for Treatment of
Moderate Amblyopia in Children,” Archives of Ophthal-
mology, Vol. 120, No. 3, 2002, pp. 268-278.
doi:10.1001/archopht.120.3.268
[9] M. X. Repka, R. T. Kraker, R. W. Beck, J. M. Holmes, S.
A. Cotter, E. E. Birch, W. F. Astle, D. L. Chandler, J. Fe-
lius, R. W. Arnold, D. R. Tien and S. R. Glaser, “A Ran-
domized Trial of Atropine vs. Patching for Treatment of
Moderate Amblyopia: Follow-Up at Age 10 Years,” Ar-
chives of Ophthalmology, Vol. 126, No. 8, 2008, pp. 1039-
1044. doi:10.1001/archopht.126.8.1039
[10] V. G. Kirk, M. M. Clausen, M. D. Armitage and R. W.
Arnold, “Preverbal Photoscreening for Amblyogenic Fac-
tors and Outcomes in Amblyopia Treatment: Early Ob-
jective Screening and Visual Acuities,” Archives of Oph-
thalmology, Vol. 126, No. 4, 2008, pp. 489-492.
doi:10.1001/archopht.126.4.489
[11] R. G. Teed, C. M. Bui, D. G. Morrison, R. L. Estes and S.
P. Donahue, “Amblyopia Therapy in Children Identified
by Photoscreening,” Ophthalmology, Vol. 117, No. 1,
2010, pp. 159-162. doi:10.1016/j.ophtha.2009.06.041
[12] K. Taylor and S. Elliott, “Interventions for Strabismic Am-
blyopia,” Cochrane database of systematic reviews, No. 8,
2011, Article ID: CD006461.
[13] S. P. Donahue and J. B. Ruben, et al., “US Preventive Ser-
vices Task Force Vision Screening Recommendations,”
Pediatrics, Vol. 127, No. 3, 2011, pp. 569-570.
doi:10.1542/peds.2011-0020
[14] R. Chou, T. Dana and C. Bougatsos, “Screening for Vi-
sual Impairment in Children Ages 1-5 Years: Systematic
Review to Update the 2004 U.S. Preventive Services
Task Force Recommendation,” Agency for Healthcare
Research and Quality (US), Rockville, 2011.
[15] A. Kemper, R. Harris, T. A. Lieu, C. J. Homer and B. L.
Whitener, “Screening for Visual Impairment in Children
Younger than Age 5 Years: A Systematic Evidence Re-
view for the U.S. Preventive Services Task Force,” Agen-
cy for Healthcare Research and Quality (US), Rockville,
2004.
[16] T. C. Wall, W. Marsh-Tootle, H. H. Evans, C. A. Farga-
son, C. S. Ashworth and J. M. Hardin, “Compliance with
Vision-Screening Guidelines among a National Sample of
Pediatricians,” Ambulatory Pediatrics, Vol. 2, No. 6,
2002, pp. 449-455.
doi:10.1367/1539-4409(2002)002<0449:CWVSGA>2.0.
CO;2
[17] P. Y. Tong, E. Enke-Miyazaki, R. E. Bassin, J. M. Tie-
lsch, D. R. Stager Sr., G. R. Beauchamp and M. M. Parks,
“Screening for Amblyopia in Preverbal Children with Pho-
toscreening Photographs. National Children’s Eye Care
Foundation Vision Screening Study Group,” Ophthalmo-
logy, Vol. 105, No. 5, 1998, pp. 856-863.
[18] Committee on Practice and Ambulatory Medicine and
Section on Ophthalmology, “Use of Photoscreening for
Children’s Vision Screening,” Pediatrics, Vol. 109, No. 3,
2002, pp. 524-525. doi:10.1542/peds.109.3.524
[19] S. Q. Longmuir, W. Pfeifer, A. Leon, R. J. Olson, L.
Short and W. E. Scott, “Nine-Year Results of a Volunteer
Lay Network Photoscreening Program of 147,809 Chil-
dren Using a Photoscreener in Iowa,” Ophthalmology,
Vol. 117, No. 10, 2010, pp. 1869-1875.
doi:10.1016/j.ophtha.2010.03.036
[20] N. S. Matta, R. W. Arnold, E. L. Singman and D. I. Sil-
bert, “Can a Photoscreener Help Us Remotely Evaluate
and Manage Amblyopia?” American Orthoptic Journal,
Vol. 61, No. 1, 2011, pp. 124-127.
doi:10.3368/aoj.61.1.124
[21] A. S. A. Moghaddam, A. Kargozar, M. Zarei-Ghanavati,
M. Najjaran, V. Nozari and M. T. Shakeri, “Screening for
Amblyopia Risk Factors in Preverbal Children Using the
Plusoptix Photoscreener: A Cross-Sectional Population-

Comparison between the PlusoptiX and IScreen Photoscreeners in Detecting Amblyopic Risk Factors in Children
12
Based Study,” British Journal of Ophthalmology, 2011,
[22] S. P. Donahue, J. D. Baker, W. E. Scott, P. Rychwalski,
D. E. Neely, P. Tong, D. Bergsma, D. Lenahan, D. Rush,
K. Heinlein, R. Walkenbach and T. M. Johnson, “Lions
Clubs International Foundation Core Four Photoscreening:
Results from 17 Programs and 400,000 Preschool Chil-
dren,” Journal of AAPOS, Vol. 10, No. 1, 2006, pp. 44-48.
doi:10.1016/j.jaapos.2005.08.007
[23] N. S. Matta, E. L. Singman and D. I. Silbert, “Perfor-
mance of the Plusoptix S04 Photoscreener for the Detec-
tion of Amblyopia Risk Factors in Children Aged 3 to 5,”
Journal of AAPOS, Vol. 14, No. 2, 2010, pp. 147-149.
[24] S. P. Donahue, R. W. Arnold and J. B. Ruben, “Preschool
Vision Screening: What Should We Be Detecting and
how Should We Report It? Uniform Guidelines for Re-
porting Results of Preschool Vision Screening Studies,”
Journal of AAPOS, Vol. 7, No. 5, 2003, pp. 314-316.
[25] P. Schmidt, M. Maguire, V. Dobson, G. Quinn, E. Ciner,
L. Cyert, M. T. Kulp, B. Moore, D. Orel-Bixler, M. Red-
ford and G. S. Ying, “Comparison of Preschool Vision
Screening Tests as Administered by Licensed Eye Care
Professionals in the Vision in Preschoolers Study,” Oph-
thalmology, Vol. 111, No. 4, 2004, pp. 637-650.
[26] M. M. Clausen and R. W. Arnold, “Pediatric eye/vision
screening. Referral Criteria for the Pedia Vision plus Op-
tix S 04 Photoscreener Compared to Visual Acuity and
Digital Photoscreening. Kindergarten Computer Photo-
screening,” Binocular Vision and Strabismus Quarterly,
Vol. 22, No. 2, 2007, pp. 83-89.
[27] W. L. Ottar, W. E. Scott and S. I. Holgado, “Photoscreen-
ing for Amblyogenic Factors,” Journal of Pediatric Oph-
thalmology and Strabismus, Vol. 32, No. 5, 1995, pp.
289-295.