Beyond screening for risk factors: objective detection of strabismus and amblyopia

The blinq™ Vision Screener in Detection of Amblyopia and Strabismus

PURPOSE

The blinq (Rebion Inc) is a new screening device designed to directly detect amblyopia and strabismus rather than amblyopia risk factors. We performed an independent assessment of the effectiveness of the blinq in detecting amblyopia and strabismus.

DESIGN

Prospective clinical validity analysis of a screening device based on sensitivity and specificity.

METHODS

Children presenting for examination in the pediatric ophthalmology clinic underwent screening with the blinq before examination by a pediatric ophthalmologist blinded to the screening results. Results of the blinq and examination findings of strabismus or amblyopia were compared.

RESULTS

In our cohort of 267 children with an average age of 6.3 years, the sensitivity of the blinq to detect amblyopia or any constant strabismus was 87.5% (78.2%-93.8%) and specificity was 51.3% (43.9%-58.7%). Using the previously described "appropriate referral gold standard" criteria, including children with intermittent strabismus and high refractive error, the sensitivity increased to 91.3% and the specificity to 63.2%. We found a high number of children (44 [16%]) upon whom the blinq timed out and were included as automatic referrals.

CONCLUSIONS

Our results support use of the blinq as a screening device to detect amblyopia and strabismus in children.

Evaluation of the Blinq Vision Screener in the Detection of Amblyopia and Strabismus in Children

Purpose

Amblyopia is a major health problem with an estimated 2% to 4% of the population affected. Screening combined with corrective measures, such as correction of refractive error and occlusion of the dominant eye, could reduce this prevalence. A new pediatric vision scanner, the blinq (Rebion, Boston, MA), studies the foveolar quality of fixation of each eye during binocular viewing. Based on the initial premise that poor quality foveolar or non-foveolar fixation is indicative of strabismus and, potentially of amblyopia, this study evaluates the effectiveness of the blinq screening device in detecting these two conditions compared to a standard ophthalmic examination (Gold Standard) based on the recommendations of the American Association for Pediatric Ophthalmology and Strabismus.

Material and Methods

A prospective study was performed on a total of 101 children between 2 and 8 years of age. These children were offered a test by the blinq screening device before a standard ophthalmological examination in the ophthalmology department of the Erasmus Hospital in Brussels, Belgium. The two tests were then compared.

Results

In a pediatric population heightened with amblyopia and strabismus (prevalence of 33.4%) and based on the Gold Standard Examination, the blinq device showed a specificity of 73.1% (95% confidence interval [CI] = 60.9%–83.2%) with a sensitivity of 91.2% (95% CI = 76.3%–98.1) to detect these conditions. The positive and negative predictive values were 63.3% (95% CI = 53.4%–72.2%) and 94.2% (95% CI = 84.6%–98%) respectively. The positive likelihood ratio (LR+) was 3.39 (95% CI = 2.26–5.11) for a negative likelihood ratio of 0.12 (95% CI = 0.04–0.36).

Conclusions

The blinq device has good sensitivity, but insufficient specificity to be used alone in the first line of screening. Whereas other devices on the market detect risk factors that may lead to amblyopia, the blinq pediatric vision scanner detects poor foveolar fixation and strabismus, giving it a potential advantage in sensitivity to directly detect strabismus, including microstrabismus. The blinq does not detect refractive abnormalities, however, and will therefore need to be improved in the future to be used alone in pediatric vision screening.

Translational Relevance

The blinq device detects visual axis alignment abnormalities with potential impact in the early detection of strabismus and subsequent associated amblyopia.

Canon CP-TX1 camera - As a screening tool for amblyogenic risk factors

Purpose:

To evaluate the Canon CP-TX1 camera as a screening tool for ARFs in a pediatric population and estimate the prevalence of ARFs.

Methods:

In a pediatric outpatient space, largely in the immunization clinic, after obtaining parental consent, we encouraged children to be photographed from a distance of 5 feet in a dim room by using a CP-TX1 camera with the red-eye reduction feature off. Based on the captured red reflex, children were labeled as normal (symmetrical red reflexes in the two eyes, with no visible crescents); all others were considered as abnormal or positive for ARFs. All photographed children were assessed by an optometrist/refractionist for VA by age-appropriate methods. Data were entered into a 2 × 2 contingency table on statpages.org, and diagnostic indices were calculated with 95%CI.

Results:

With a sample of 262 children, we obtained a sensitivity of 0.82, a specificity of 0.98, a positive predictive value of 0.92, a negative predictive value of 0.94, a positive likelihood ratio of 41.06, a negative likelihood ratio of 0.17, and a prevalence of 0.24 for ARFs

Conclusion:

CP-TX1 performed well as a screening tool to identify ARFs in children. Placing such a camera in an immunization clinic offers a chance to identify children with ARFs at a time when amblyopia is eminently reversible.

Multifaceted Amblyopia Screening with blinq, 2WIN, and PDI Check

BACKGROUND

Novel devices target different facets of amblyopia risk factors (ARFs). Through birefringence, the Rebion blinq assesses binocular foveation. The Adaptica 2WIN is a multiradial infrared photorefractor that also estimates ocular alignment. PDI Check is a forced-choice, dynamic near-vision game for the autostereoscopic Nintendo 3DS.

METHODS

New and returning patients to a pediatric ophthalmology clinic had concomitant confirmatory exams after all three vision screens had been validated with ROC curves, Bland-Altman plots, and Alaska Blind Child Discovery ellipsoid grades. Exam outcomes were classified by ARF visual acuity, strabismus, binocularity, and refractive errors following the 2021 AAPOS guidelines and Bosque-Hunter rubric for the blinq.

RESULTS

A total of 202 ethnically diverse students aged 10±4 (4-19) years, 33% treatment-naïve, had a high (58%) prevalence of ARFs. Linear logMAR visual acuity, intereye differences, stereo and three-cone color correlated well between PDI Check and exams. Mean score on the 2WIN matched sphero-cylinder exam with ellipsoid scoring was 2.1±1.5. For AAPOS 2021 refractive plus strabismus, sensitivity/specificity for PDI Check was 68%/59%, 2WIN 72%/95%, and blinq 87%/32%. For the amblyopia or strabismus rubric, PDI Check was 79%/68%, 2WIN 56%/65%, and blinq 94%/37%.

CONCLUSION

Each device had advantages and disadvantages in screening this cohort of older, high-prevalence students, many of whom had already been treated. Validation methods should cover more than just refraction, as the new 2021 AAPOS guidelines do.

Pediatric Non-Refractive Vision Screening with EyeSwift, PDI Check and Blinq: Non-Refractive Vision Screening with Two Binocular Video Games and Birefringent Scanning

BACKGROUND

The purpose of this paper is to validate three recent non-refractive devices that target sensory and/or strabismus risk factors for amblyopia. EyeSwift® with eye tracking and PDI Check on autostereoscopic Nintendo 3DS are video games that estimate acuity, binocularity and color. The Rebion blinq assesses foveation by birefringence.

METHODS

Students were consented to be screened by each device as if by a school nurse before confirmatory examination with optimized, refined refraction. Results were compared with correlation and Bland Altman plots while screening ability was compared with 2021 AAPOS Guidelines and the strabismus-amblyopia rubric proposed by David Hunter.

RESULTS

A total of 77 ethnically diverse students, aged 11±4 (4-19) years had a 77% prevalence of 2021 risk factors. Near visual acuity, inter-eye difference and stereopsis correlated significantly (p<0.01) for the EyeSwift® (r2 0.14, 0.06 and 0.45) and PDI Check (r2 0.23, 0.22 and 0.32). The sensitivity/specificity to target 2021-AAPOS: Hunter-rubric for EyeSwift® was 82%/56%: 74%/62%, for PDI Check was 75/64%: 69%/69% and for blinq 75/48%: 82%/39%. Sensitivity/specificity for the seven color-deficient students was 86%/84% for EyeSwift® and 100%/81% for PDI Check. Screening time was 96±19 s for PDI Check and 375±102 s for EyeSwift but less than 25 s for blinq.

CONCLUSION

Reliable near visual acuity, stereo and color testing were obtained from the two binocular and touch screen devices often with minimal coaching of the student. The blinq rapidly gives an estimate of whether both eyes are steadily fixing, and the ProVersion predicted 100% which eye is deviated or amblyopic. Non-refractive validation metrics were beneficial.

Recent Advances in Screening and Treatment for Amblyopia

Amblyopia is the most common cause of monocular visual impairment in children, with a prevalence of 2-3%. Not only is visual acuity reduced in one eye but binocular vision is affected, fellow eye deficits may be present, eye-hand coordination and reading can be affected, and self-perception may be diminished. New technologies for preschool vision screening hold promise for accessible, early, and accurate detection of amblyopia. Together with recent advances in our theoretical understanding of amblyopia and technological advances in amblyopia treatment, we anticipate improved visual outcomes for children affected by this very common eye condition. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.

Prediction and cost-effectiveness comparison of amblyopia screening methods at ages 3-4 years

PURPOSE

Compare the performance of different amblyopia screening tests.

METHODS

Based on exploratory factor analyses (EFA) of different screening tests performed in 3295 children, we created models of screening strategies in a matrix with: uncorrected visual acuity (UCVA), Plusoptix measurements (PO), Randot Stereo-test (SR), and Cover-Test (CT). Receiver Operating Characteristic (ROC) curves and confusion matrix were used to compare performance of different model's algorithm to predict new diagnosis of amblyopia. Estimated screening costs per screened and treated child were compared.

RESULTS

Regression analyses revealed that, although all models predicted amblyopia (all p < 0.001), only models including PO or UCVA had higher prediction capacity (R² > 0.4) and better discriminating ROC curves (AUC > 0.95; p < 0.001). For 96% sensitivity, UCVA + PO was the most cost-effective model, since the estimated average screening costs per treated child, almost doubled and tripled if using PO or UCVA alone, respectively, versus using both exams. When UCVA + PO is not possible to implement, adding SR to either UCVA or PO resulted in cost-savings of 28% and 18%, respectively.

CONCLUSIONS

In a previous unscreened population, aged 3-4 years, screening programs using either UCVA or PO alone, should reconsider doing both tests simultaneously, since, for a high level of sensitivity, using simultaneously UCVA + PO is more cost-effective, per screened, and treated amblyopia. Concerns relating higher time-consuming exams for the combination of UCVA + PO should be surpassed, since costs per treated child drop considerably. When children benefit from good primary-care routine examinations since birth, no benefit was found for using CT in a screening setting. SR showed little benefit.

Evaluation of the blinq vision scanner for detection of amblyopia and strabismus

PURPOSE

To report the results of a clinical study designed to evaluate the accuracy of the blinq pediatric vision scanner, which detects amblyopia and strabismus directly by means of retinal polarization scanning, unlike other vision screening devices, which infer possible disease based on detection of refractive risk factors.

METHODS

Subjects 1-20 years of age were prospectively enrolled in this cross-sectional diagnostic accuracy study with planned enrollment of 200. All enrolled subjects were tested by individuals masked to the diagnosis, followed by complete ophthalmologic examination by pediatric ophthalmologists masked to the screening result. Patients previously treated for amblyopia or strabismus were analyzed separately.

RESULTS

The study cohort comprised 193 subjects, 53 of whom had been previously treated, leaving 140 treatment-naïve subjects, including 65 (46%) with amblyopia or strabismus, 11 (8%) with risk factors/suspected binocular vision deficit without amblyopia/strabismus, and 64 (46%) controls. Sensitivity was 100%, with all 66 patients with referral-warranted ocular disease referred. Five patients with intermittent strabismus receiving pass results were deemed "acceptable pass" when considering patient risk factors and amblyogenic potential. Specificity was 91%, with 7 incorrect referrals. Subanalysis of children aged 2-8 years (n = 92) provided similar results (sensitivity 100%; specificity 89%).

CONCLUSIONS

In this study cohort, the blinq showed very high sensitivity and specificity for detecting referral-warranted unilateral amblyopia and strabismus. Implementation of the device in vision screening programs could lead to improved rates of disease detection and reduction in false referrals.

Validation of the Pediatric Vision Scanner in a normal preschool population

PURPOSE

To assess the Pediatric Vision Scanner (PVS), a handheld vision screening device designed to test for amblyopia and strabismus, in a general pediatric population.

METHODS

In this prospective study, trained research staff screened 300 eligible children 24-72 months of age with no known eye conditions for amblyopia and strabismus using the PVS. A pediatric ophthalmologist masked to PVS screening results then performed a comprehensive eye examination. Sensitivity and specificity of the PVS was calculated with a 95% confidence interval.

RESULTS

Based on the gold standard eye examination, 6 children (2%) had amblyopia and/or strabismus. The PVS detected all 6 cases, yielding a sensitivity rate of 100% (95% CI, 54%-100%). The PVS referred 45 additional children (15%) who had normal ophthalmic findings, yielding a specificity rate of 85% (95% CI, 80%-89%). The median acquisition time for the PVS was 28 seconds.

CONCLUSIONS

The PVS detected amblyopia with high sensitivity in a nonenriched pediatric population. The device would allow children with amblyopia and/or strabismus to be referred to an eye care specialist as early as 2 years old. Given its short acquisition time, the PVS can be implemented in a pediatric clinic with minimal impact on workflow.

2020 Evaluation of Portable Vision Screening Instruments

Amblyopia is the most common cause of preventable visual impairment in children and occurs as a result of unilateral or bilateral impairment in best-corrected visual acuity. Early diagnosis and proper treatment are crucial to prevent poor visual outcomes in adulthood. Advances in technology have provided more objective diagnostic tools, which can now be used by a wide range of healthcare providers. Here, we highlight tools that have gained popularity in the past two decades and compare clinically relevant parameters to guide primary care providers seeking to incorporate instrumental vision screening in pediatric patient care.

Prevalence and associated risk factors for childhood strabismus in Lhasa, Tibet, China: a cross-sectional, school-based study

Background

To estimate the prevalence of strabismus and associated risk factors among grade one school children in Lhasa, Tibet, China.

Methods

The Lhasa Childhood Eye Study (LCES) was a cross-sectional, school-based childhood study conducted in Grade one students from primary schools in Lhasa, Tibet, China. Comprehensive ophthalmic examinations and basic systemic examinations were evaluated. A questionnaire survey containing information about children, as well as parents’ information, was sent to the corresponding parents of eligible children. The prevalence of strabismus and its 95% confidence interval was estimated. Univariate and multivariate logistic regression analyses were conducted to determine the associated risk factors.

Results

A total of 1942 eligible grade one students were enrolled, of which 1856 participants completed all examinations. The average age was 6.83 ± 0.46 years, 53% of participants were boys and 1762 were the Tibetan Minority. Over all, the prevalence of strabismus was 68/1856 (3.7%) (95%CI: 2.81,4.52), with no difference between the ages, genders, ethnicities and body mass index, while tilting one’s head when writing may be a risk factor for strabismus (P = 0.004). Strabismus students had mean best corrected visual acuity of 0.16 ± 0.28(LogMAR), over 50% patients with esotropia were hyperopic, and participants who had stereopsis impairments showed a significant difference between esotropia and exotropia (P = 0.026).

Conclusions

The prevalence of strabismus in LCES was 3.7%, which is higher than previous reports from Chinese childhood epidemiology studies. Strabismus is a common contributing factor to amblyopia. Tilting one’s head when writing may be a risk factor. Esotropia is more likely to affect stereopsis and be associated with the refractive state of hyperopia.

Trial registration

The study has finished the clinical registration on Chinese Clinical Trial Registry. (http://www.chictr.org.cn, ChiCTR1900026693).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-020-01732-2.

Comparative AAPOS Validation of the Birefringent Amblyopia Screener with Isolated Small-Angle Strabismus

BACKGROUND

The Rebion blinq binocular birefringent ocular alignment screener was recently commercially released, but it did not yet have validation by American Association for Pediatric Ophthalmology and Strabismus (AAPOS) uniform guidelines.

METHODS

Children and adults from a high-risk eye practice had screening by blinq with validation by AAPOS 2003 guidelines. Then, the blinq was compared to the Adaptica 2WIN with CR corneal reflex strabismus estimation by AAPOS 2003 guidelines plus additional efforts to identify patients with diminished binocularity.

RESULTS

Blinq in 100 patients compared to 2003 AAPOS amblyopia risk factors (ARF) had sensitivity 67%, specificity 75% and PPV of 82%. Both blinq and 2WIN were completed by 87 patients median age 6.5 years. Sensitivity, specificity and positive predictive value (PPV) for blinq were 75%, 68% and 81% whereas 2WIN had 91%, 68% and 84%. The blinq referred two young patients with isolated, small-angle strabismic amblyopia that 2WIN refractive function passed.

CONCLUSION

Despite its non-refractive design to identify binocular foveation, blinq performed well with refractive and strabismic uniform risk factors and a PPV greater than 80%.

CLINICAL TRIALS REGISTRY

NCT04195711.

Evaluation of a smartphone photoscreening app to detect refractive amblyopia risk factors in children aged 1-6 years

Purpose

To determine the specificity and sensitivity of a smartphone app (GoCheckKids [GCK] used as a photoscreening tool on the iPhone 7 to detect refractive amblyopia risk factors in children aged 1–6 years.

Participants and methods

A prospective, multicenter, 10-month evaluation of children aged 1–6 years old who underwent photoscreening with the GCK app to detect amblyopia risk factors. The first acceptable quality photograph of each study subject was evaluated by trained technicians using GCK’s proprietary automated image processing algorithm to analyze for amblyopia risk factors. Trained graders, masked to the cycloplegic clinical data, remotely reviewed photographs taken with the app and compared results to the gold standard pediatric ophthalmology examinations using the 2013 American Association for Pediatric Ophthalmology & Strabismus amblyopia risk factor guidelines. Primary outcome was the ability of the GCK app to identify amblyopia risk factors compared to the cycloplegic refraction.

Results

There were 287 patient images analyzed. The overall sensitivity and specificity in detecting amblyopia risk factors were 76% and 85%, respectively using manual grading. The overall automated grading results had a sensitivity and sensitivity in detecting amblyopia risk factors of 65% and 83%, respectively.

Conclusion

The GCK smartphone app is a viable photoscreening device for the detection of amblyopia risk factors in children aged 1–6 years.

Vision screening at two years does not reduce the prevalence of reduced vision at four and a half years of age

BACKGROUND

There is currently insufficient evidence to recommend vision screening for children < 36 months of age. This study assessed the effect of comprehensive vision screening, as well as the sensitivity of age-appropriate vision tests, at two years of age on habitual visual acuity at 4.5 years of age.

METHODS

Children born at risk of neonatal hypoglycaemia (n = 477) underwent vision assessment at 54 ± 2 months of age including measurement of monocular and binocular habitual visual acuity, assessment of binocularity and stereopsis. Of these children, 355 (74.4 per cent) had also received vision screening at two years of age (mean age = 24± 1 months), while 122 were not screened.

RESULTS

Eighty (16.8 per cent) children were classified as having reduced vision at 4.5 years of age, but the prevalence of reduced vision did not differ between children who had previously been screened at two years of age and those who had not (15.5 per cent versus 20.5 per cent, p = 0.153). However, children with reduced vision at 4.5 years of age were more likely to have had visual abnormalities requiring referral detected at two years of age (p = 0.02). Visual acuity and mean spherical equivalent autorefraction measurements were also worse (higher values) in two-year-old children who were later classified with reduced habitual visual acuity (p = 0.031 and p = 0.001, respectively). Nevertheless, unaided binocular visual acuity, non-cycloplegic refractive error, and stereopsis at two years all showed poor sensitivity and specificity for predicting visual outcomes at 4.5 years of age.

CONCLUSION

Our findings do not support the adoption of early vision screening in children as current vision tests suitable for use with two-year-old children have poor sensitivity for predicting mild-moderate habitual vision impairment at 4.5 years of age.

Early diagnosis of amblyopia

Amblyopia can be improved or eliminated more easily when treated early in life. Because amblyopia in older children is generally less responsive to treatment (Holmes et al., 2011), there is a premium on the early identification of amblyopia and its risk factors and the subsequent treatment thereof. Clinical preference is to institute treatment in children before 7 years of age when an optimal visual outcome is typically easier to obtain.

Instrument-based pediatric vision screening

PURPOSE OF REVIEW

The purpose is to review currently available instruments for vision screening in young children.

RECENT FINDINGS

Instrumentation continues to evolve. Although the current generation of photoscreeners and autorefractors strive to identify amblyopia risk factors, newer technology aims to directly identify amblyopia in young children. Acceptance of instrument-based vision screening for this population has led to increased reimbursement for the procedure in primary care practices.

SUMMARY

Instrument-based vision screening in the young child is an accepted method of screening for amblyopia. Innovations in instrumentation will continue to improve its implementation.

Variability of Ocular Deviation in Strabismus

IMPORTANCE

In strabismus, the fixating eye conveys the direction of gaze while the fellow eye points at a peripheral location in space. The stability of the eyes may be reduced by the absence of a common target.

OBJECTIVE

To quantify the stability of eye position in strabismus and to measure variability in the ocular deviation.

DESIGN, SETTING, AND PARTICIPANTS

From 2010 to 2014, a prospective comparative case study of 25 patients with alternating exotropia with normal visual acuity in each eye and 25 control individuals was conducted in a laboratory at a tertiary eye center. A video eye tracker was used to measure the position of each eye while participants alternated fixation on the center of a cross under dichoptic conditions or scanned pictures of natural scenes.

MAIN OUTCOMES AND MEASURES

Spatial and temporal variability in the position of the fixating eye and the nonfixating eye in patients with strabismus and control individuals, quantified by the log area of ellipses containing 95% of eye positions or mean SDs of eye position.

RESULTS

In the 25 patients with strabismus, the mean (SD) age was 28 (14) years (range, 8-55 years) and the mean (SD) ocular deviation was 14.2° (5.9°) (range, 4.4°-22.4°). In the patients with strabismus, the mean position variability (1.80 log units; 95% CI, 1.66-1.93) for the deviating eye was greater than for the fixating eye (1.26 log units; 95% CI, 1.17-1.35) (P < .001). The fixating eye of patients with strabismus was more variable in position than the fixating eye of individuals without strabismus (0.98 log units; 95% CI, 0.88-1.08) (P < .005).

CONCLUSIONS AND RELEVANCE

In patients with strabismus, even without amblyopia, the deviated eye is more variable in position than the fixating eye. Both eyes are less stable in position than the eyes of control individuals, which indicates that strabismus impairs the ability to fixate targets steadily. Saccades contribute to variability of the deviation angle because they are less conjugate in patients with strabismus.

New pediatric vision screener, part II: electronics, software, signal processing and validation

Background

We have developed an improved pediatric vision screener (PVS) that can reliably detect central fixation, eye alignment and focus. The instrument identifies risk factors for amblyopia, namely eye misalignment and defocus.

Methods

The device uses the birefringence of the human fovea (the most sensitive part of the retina). The optics have been reported in more detail previously. The present article focuses on the electronics and the analysis algorithms used. The objective of this study was to optimize the analog design, data acquisition, noise suppression techniques, the classification algorithms and the decision making thresholds, as well as to validate the performance of the research instrument on an initial group of young test subjects—18 patients with known vision abnormalities (eight male and 10 female), ages 4–25 (only one above 18) and 19 controls with proven lack of vision issues. Four statistical methods were used to derive decision making thresholds that would best separate patients with abnormalities from controls. Sensitivity and specificity were calculated for each method, and the most suitable one was selected.

Results

Both the central fixation and the focus detection criteria worked robustly and allowed reliable separation between normal test subjects and symptomatic subjects. The sensitivity of the instrument was 100 % for both central fixation and focus detection. The specificity was 100 % for central fixation and 89.5 % for focus detection. The overall sensitivity was 100 % and the overall specificity was 94.7 %.

Conclusions

Despite the relatively small initial sample size, we believe that the PVS instrument design, the analysis methods employed, and the device as a whole, will prove valuable for mass screening of children.

High specificity of the Pediatric Vision Scanner in a private pediatric primary care setting

PURPOSE

To determine the specificity of the Pediatric Vision Scanner, a binocular retinal birefringence scanner, in its intended setting, a pediatric primary care office.

METHODS

A total of 102 preschool children (age 2-6 years) were screened during a well-child pediatric visit using the Pediatric Vision Scanner and the SureSight Autorefractor and completed a masked comprehensive pediatric ophthalmic examination (gold standard examination).

RESULTS

Based on the gold standard examination, one child had anisometropic amblyopia, and the remaining 101 had no amblyopia or strabismus. Specificity of the Pediatric Vision Scanner was 90% (95% CI, 82%-95%) while specificity of the SureSight was 87% (95%CI, 79-93%). Combining these results with the sensitivity of the devices determined in our previous study conducted in a pediatric ophthalmology office setting, the positive likelihood ratio for the Pediatric Vision Scanner was 10.2; for the SureSight, 5.0. The negative likelihood ratio for the Pediatric Vision Scanner was 0.03; for the SureSight, 0.42, a significant difference.

CONCLUSIONS

The Pediatric Vision Scanner had high specificity (90%) in screening for amblyopia and strabismus as part of a pediatric well-child visit. Likelihood ratio analysis suggests that affected children have a high probability of being correctly identified by the Pediatric Vision Scanner. The high level of confidence conferred by Pediatric Vision Scanner screening may remove an important barrier to vision screening in pediatric primary care.

Performance of the Plusoptix A09 photoscreener in detecting amblyopia risk factors in Chinese children attending an eye clinic

Purpose

To assess the accuracy of the Plusoptix A09 photoscreener in detecting amblyopia risk factors in children and determine referral criteria when using Plusoptix A09 for a large-scale vision screening.

Methods

Pediatric patients attending our eye clinic underwent a comprehensive ophthalmic examination that included photorefraction, orthoptic examination, anterior segment assessment, fundus examination and cycloplegic retinoscopy. The measurements were collected for statistical analyses.

Results

One hundred and seventy-eight children (mean age ± SD: 6.2±2.4 years, range: 2.2 to 14.1 years) were included in the study. The mean spherical equivalent (SE) obtained using Plusoptix A09 (P_SE) was 0.57 D lower than that obtained from cycloplegic retinoscopy (CR_SE) (P = 0.00). However, there was no statistically significant difference of Jackson cross cylinder J₀ and J₄₅ between Plusoptix A09 (P_J) and cycloplegic retinoscopy (CR_J) (P = 0.14, P = 0.26). The relationship of SE obtained from Plusoptix A09 and SE obtained from cycloplegic retinoscopy was presented as the equation: CR_SE = 0.358 + 0.776 P_SE + 0.064 P_SE² + 0.011 P_SE³. Based on the Receiver Operating Characteristic (ROC) curve, the Plusoptix A09 had an overall sensitivity of 94.9% and specificity of 67.5% for detecting refractive amblyopia risk factors. The sensitivity and specificity of the Plusoptix A09 for detection of strabismus were 40.7% and 98.3%, respectively; detection of amblyopia and/or strabismus was 84.7% and 63.2%, respectively.

Conclusions

The Plusoptix A09 photoscreener underestimated hyperopia and overestimated myopia according to SE when compared with cycloplegic retinoscopy. The accuracy of the Plusoptix A09 in detecting amblyopia risk factors in children could be improved by the regression equation and optimized criteria for refractive amblyopia risk factors developed in the present study. Moreover, the Plusoptix A09 photoscreener is not suitable for a large-scale strabismus screening when it is applied solely.

Current Understanding of What Infants See

The current understanding of what infants see varies greatly among healthcare and education specialists. Even among ophthalmologists and pediatric neurologists in charge of clinical examinations of infants, opinions vary on what infants perceive, recognize, and use for communication and learning. It is, therefore, of interest to review publications from several specialties to learn whether new information is available on the development of visual functions and use of vision. Ten percent of total publications on this subject are reviewed here based on the usefulness of their content for improving early diagnosis and intervention of vision disorders in infants.