Multi-ethnic Pediatric Eye Disease Study Group. Prevalence of amblyopia and strabismus in African American and Hispanic children ages 6 to 72 months the multi-ethnic pediatric eye disease study

Early reconstruction surgery resolving visual occlusion and ocular malformation: a case report

Congenital ocular malformation may lead to failure of the development of ocular regions and visual function in the pediatric population. Orbital bones are established within the first 2 months of embryogenesis. Any abnormalities may lead to failure in development of the ocular region. In this case report, we present a newborn with congenital canthus malposition, a distorted tarsus, and mild enophthalmos caused by an embryogenesis fibroma, which although rare, can result in amblyopia. Surgical resection of the fibroma followed by orbital reconstruction of the canthus, correction of malposition and tarsus extension were performed. Twelve months and 5 years follow-up showed no recurrence and the visual acuity was 20/20 in the left eye and 16/20 in the right. The deformity of the left orbit was corrected without complications and was symmetrical with the right side. This is the first known case of children with embryonic fibroma. It is likely that early reconstruction surgery may avoid visual occlusion and ocular malformation.

Normative visual acuity in infants and preschool-aged children in Sydney

PURPOSE

To provide population-based normative visual acuity (VA) by age, in children participating in the Sydney Paediatric Eye Disease Study aged 6 to <72 months.

METHODS

Monocular VA was measured using the Amblyopia Treatment Study (ATS HOTV) protocol (24 to <72 months). Some children were also tested using linear ETDRS or HOTV logMAR VA charts (30 to <72 months). If unable to perform recognition acuity, the Teller Acuity Cards II (TAC II) was performed (6 to <42 months). Children with significant refractive error or ocular disease were excluded.

RESULTS

Improvement in VA with age was shown on all three vision tests (all p < 0.0001). Mean VA using ATS HOTV (n = 836) was 0.13 logMAR (6/8) at <36 months, which improved to -0.01 (6/6) at 66 to <72 months. Mean ETDRS/HOTV (n = 399) VA was 0.26 logMAR (6/11) at <36 months, which improved to 0.1 (6/7.5) at 66 to <72 months. Mean monocular TAC II (n = 442) was 5.7 cycles/degree (0.72 logMAR) at 6 to <9 months and improved to 12.4 cycles/degree (0.38 logMAR) at age 30 to <33 months. Associations with ATS HOTV VA included prematurity (p = 0.027) and socio economic status (SES) factors such as home ownership (p = 0.039) and employment of one (p = 0.019) or both parents (p = 0.003).

CONCLUSIONS

VA norms in children improved with age and were different according to the VA test used. Low SES was associated with poorer VA, supporting the need for test specific VA norms to be established for different populations. The ATS HOTV appears to be the best test to use for vision screening due to its lower false positive referral rate.

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

IMPORTANCE

Commercially available automated vision screening devices assess refractive risk factors, not amblyopia or strabismus, underreferring affected children and overreferring healthy children. Nearly half of affected children are not identified until after age 5 years, when treatment is less effective.

OBJECTIVES

To determine the diagnostic accuracy of the Pediatric Vision Scanner (PVS), a binocular retinal birefringence scanner, to objectively identify strabismus and amblyopia, and to compare retinal birefringence screening with a widely used automated pediatric screening device.

DESIGN, SETTING, AND PARTICIPANTS

Three hundred consecutive preschool children (aged 2-6 years) were screened using the PVS and the SureSight Autorefractor at 2 pediatric ophthalmology private practices. A masked comprehensive pediatric ophthalmic examination provided the gold standard for determining sensitivity and specificity for each screening device.

MAIN OUTCOMES AND MEASURES

The primary outcome was sensitivity and specificity of the PVS for detecting the targeted conditions, strabismus and amblyopia, in children aged 2 to 6 years. Secondary outcomes included the positive and negative likelihood ratios of the PVS for identifying the targeted conditions. In addition, sensitivity, specificity, and positive and negative likelihood ratios of the SureSight Autorefractor for the targeted conditions were assessed in the same cohort of children.

RESULTS

Of the 300 patients, 188 had strabismus only, amblyopia only, or both, and 112 had no strabismus or amblyopia. The sensitivity of the PVS to detect strabismus and amblyopia (0.97; 95% CI, 0.94-1.00) was significantly higher than that of the SureSight Autorefractor (0.74; 95% CI, 0.66-0.83). Specificity of the PVS for strabismus and amblyopia (0.87; 95% CI, 0.80-0.95) was significantly higher than that of the SureSight Autorefractor (0.62; 95% CI, 0.50-0.73).

CONCLUSIONS AND RELEVANCE

The PVS identified children with strabismus and/or amblyopia with high sensitivity, outperforming the SureSight Autorefractor. Accurate, early detection of these conditions could improve long-term vision outcomes of affected preschool children.

A randomized trial comparing part-time patching with observation for children 3 to 10 years of age with intermittent exotropia

OBJECTIVE

To determine the effectiveness of prescribed part-time patching for treatment of intermittent exotropia (IXT) in children.

DESIGN

Multicenter, randomized clinical trial.

PARTICIPANTS

Three hundred fifty-eight children 3 to <11 years of age with previously untreated (except for refractive correction) IXT and near stereoacuity of 400 seconds of arc or better were enrolled. Intermittent exotropia met the following criteria: (1) IXT at distance OR constant exotropia at distance and either IXT or exophoria at near; (2) exodeviation (tropia or phoria) of at least 15 prism diopters (PD) at distance or near by prism and alternate cover test (PACT); and (3) exodeviation of at least 10 PD at distance by PACT.

METHODS

Participants were assigned randomly either to observation (no treatment for 6 months) or to patching for 3 hours daily for 5 months, with a 1-month washout period of no patching before the 6-month primary outcome examination.

MAIN OUTCOME MEASURES

The primary outcome was deterioration at either the 3-month or the 6-month follow-up visit, defined as: (1) constant exotropia measuring at least 10 PD at distance and near by simultaneous prism and cover test, and/or (2) near stereoacuity decreased by at least 2 octaves from baseline, both assessed by a masked examiner and confirmed by a retest. Participants who were prescribed any nonrandomized treatment without first meeting either deterioration criteria also were counted as having deteriorated.

RESULTS

Of the 324 participants (91%) completing the 6-month primary outcome examination, deterioration occurred in 10 of the 165 participants (6.1%) in the observation group (3 of these 10 started treatment without meeting deterioration criteria) and in 1 of the 159 participants (0.6%) in the part-time patching group (difference, 5.4%; lower limit of 1-sided exact 95% confidence interval, 2.0%; P = 0.004, 1-sided hypothesis test).

CONCLUSIONS

Deterioration of previously untreated childhood IXT over a 6-month period is uncommon with or without patching treatment. Although there is a slightly lower deterioration rate with patching, both management approaches are reasonable for treating children 3 to 10 years of age with IXT.

Effect of gestational age and birth weight on the risk of strabismus among premature infants

IMPORTANCE

Strabismus causes irreversible vision loss if not detected and treated early. It is unclear whether birth weight (BW) and gestational age (GA) are risk factors for strabismus.

OBJECTIVE

To estimate the effect of BW and GA on the likelihood of premature infants developing strabismus.

DESIGN, SETTING, AND PARTICIPANTS

In this longitudinal cohort analysis, we monitored a group of premature children from birth to determine the proportion that developed strabismus and the timing of the first strabismus diagnosis. Multivariable Cox regression analyses assessed the relationships of BW and GA with the development of strabismus. Regression models were adjusted for other risk factors for strabismus, sociodemographic factors, and ocular comorbidities. The analysis included 38,055 otherwise healthy children born prematurely who were enrolled for more than 6 months in a nationwide US managed care network between 2001 and 2011 in communities throughout the United States.

EXPOSURES

Birth weight less than 2000 g or GA of 32 weeks or less.

MAIN OUTCOMES AND MEASURES

Hazard ratios (HRs) for strabismus with 95% CIs.

RESULTS

Of 38,055 otherwise healthy children who were born prematurely, 583 received a diagnosis of strabismus later in life. The cumulative incidence of strabismus was 3.0% at 5 years. Controlling for GA and other covariates, infants born with BW less than 2000 g had a 61% increased hazard (HR, 1.61; 95% CI, 1.22-2.13) of developing strabismus. Controlling for BW and other covariates, there was no significant association between strabismus and GA (HR, 0.98; 95% CI, 0.69-1.38). Among premature infants with BW of less than 2000 g, a GA of 32 weeks or less conveyed no additional increased risk for developing strabismus relative to infants born after 32 weeks (HR, 1.27; 95% CI, 0.86-1.88). In contrast, among infants with a GA of 32 weeks or less, BW of less than 2000 g conveyed a 14-fold increase in the risk of strabismus relative to BW of 2000 g or more (HR, 14.39; 95% CI, 1.99-104.14).

CONCLUSIONS AND RELEVANCE

Independent of GA, very low BW conferred a large increase in strabismus risk among premature infants. In contrast, independent of BW, GA did not significantly affect the risk of strabismus. Updates to existing guidelines in the pediatric and ophthalmic literature should be considered, highlighting the importance of BW rather than GA and alerting clinicians about the need for careful monitoring of premature infants with low BW for strabismus.

Ten-Year Results of Home Vision-Screening Test in Children Aged 3-6 Years in Seoul, Korea

PURPOSE

To characterize the prevalence of refractive error and amblyopia among three- to six-year-old children during the period from 2002 to 2011.

METHODS

About 31,400 children annually (from 16,592 to 40,816) during the period from 2002 to 2011 were enrolled. The preschool vision screening was performed by the Korean Foundation for the Prevention of Blindness (KFPB) annually during a period that extended from March to September. We reviewed the KFPB annual report about the home vision-screening test as performed during the period from 2002 to 2011. Changes in the prevalence and types of refractive error, strabismus, and amblyopia that manifested throughout this period were analyzed.

RESULTS

The prevalence of refractive errors ranged from 1.10% in 2002 to 0.42% in 2011. The prevalence of hyperopia and myopia changed little throughout the 10-year study period. Myopia and hyperopia were equally common among the population examined (χ(2)-test, p = 0.137). The prevalence of anisometropia decreased over time. The annual prevalence of amblyopia ranged from 0.39% to 0.06%, while the overall prevalence of amblyopia dropped from 0.25% in 2002 to 0.06% in 2011. The prevalence of strabismus was highest in 2006 (0.30%) and had decreased by 0.06% in 2011. The type of strabismus showed no significant difference over time (χ(2)-test, p = 0.579).

CONCLUSIONS

The prevalence of amblyopia, refractive error, anisometropia, and strabismus was lower in 2011 than in early 2000. The prevalence of hyperopia and myopia as well as strabismus remained similar throughout the study period.

Treatment of periorbital infantile haemangiomas: a systematic literature review on propranolol or steroids

AIM

The aim of this study was to compare the efficacy and safety of propranolol versus corticosteroids for the treatment of periorbital infantile haemangiomas (IHs).

METHODS

A literature review using PubMed, Ovid Medline, EBSCO, Springer, Web of Knowledge, Cochrane Library, CNKI and associated references before 2 March 2013 was conducted. The main outcomes were distribution of locations, response rate, rebound growth rate, spherical and cylinder power before and after treatment, amblyopia rate and adverse events.

RESULTS

Thirty-one studies including 425 patients met the inclusion criteria. A total of 70.6% of patients were female, 89.6% of the periorbital IHs were located in the upper or lower eyelid area. The most common administration routes involved oral propranolol and intralesional injection of corticosteroids. The mean response rate was 94.0% for propranolol and 82.3% for corticosteroid (P = 0.001). The rebound growth rate was 13.9% for propranolol and 12.0% for steroids (P = 0.71). Astigmatism was reduced in both propranolol and steroid studies (P < 0.0001, P < 0.0001), but a significant reduction in spherical power was only demonstrated in propranolol studies (P = 0.005). A total of 31.1% of patients treated with corticosteroids developed post-operative amblyopia compared with 16.7% of patients treated with propranolol (P = 0.04). Oral propranolol seemed to induce more temporary adverse events than intralesional corticosteroids administration (24.0% vs. 9.6%, P = 0.006).

CONCLUSION

Propranolol may represent an effective therapy for periorbital IHs compared with the use of corticosteroids; however, further randomised control studies are needed to compare adverse events.

Strabismus genetics across a spectrum of eye misalignment disorders

Eye misalignment, called strabismus, is amongst the most common phenotypes observed, occurring in up to 5% of individuals in a studied population. While misalignment is frequently observed in rare complex syndromes, the majority of strabismus cases are non-syndromic. Over the past decade, genes and pathways associated with syndromic forms of strabismus have emerged, but the genes contributing to non-syndromic strabismus remain elusive. Genetic testing for strabismus risk may allow for earlier diagnosis and treatment, as well as decreased frequency of surgery. We review human and model organism literature describing non-syndromic strabismus, including family, twin, linkage, and gene expression studies. Recent advances in the genetics of Duane retraction syndrome are considered, as relatives of those impacted show elevated familial rates of non-syndromic strabismus. As whole genome sequencing efforts are advancing for the discovery of the elusive strabismus genes, this overview is intended to support the interpretation of the new findings.

Prevalence of vision disorders by racial and ethnic group among children participating in head start

OBJECTIVE

To compare the prevalence of amblyopia, strabismus, and significant refractive error among African-American, American Indian, Asian, Hispanic, and non-Hispanic white preschoolers in the Vision In Preschoolers study.

DESIGN

Multicenter, cross-sectional study.

PARTICIPANTS

Three- to 5-year old preschoolers (n=4040) in Head Start from 5 geographically disparate areas of the United States.

METHODS

All children who failed the mandatory Head Start screening and a sample of those who passed were enrolled. Study-certified pediatric optometrists and ophthalmologists performed comprehensive eye examinations including monocular distance visual acuity (VA), cover testing, and cycloplegic retinoscopy. Examination results were used to classify vision disorders, including amblyopia, strabismus, significant refractive errors, and unexplained reduced VA. Sampling weights were used to calculate prevalence rates, confidence intervals, and statistical tests for differences.

MAIN OUTCOME MEASURES

Prevalence rates in each racial/ethnic group.

RESULTS

Overall, 86.5% of children invited to participate were examined, including 2072 African-American, 343 American Indian (323 from Oklahoma), 145 Asian, 796 Hispanic, and 481 non-Hispanic white children. The prevalence of any vision disorder was 21.4% and was similar across groups (P=0.40), ranging from 17.9% (American Indian) to 23.3% (Hispanic). Prevalence of amblyopia was similar among all groups (P=0.07), ranging from 3.0% (Asian) to 5.4% (non-Hispanic white). Prevalence of strabismus also was similar (P=0.12), ranging from 1.0% (Asian) to 4.6% (non-Hispanic white). Prevalence of hyperopia >3.25 diopter (D) varied (P=0.007), with the lowest rate in Asians (5.5%) and highest in non-Hispanic whites (11.9%). Prevalence of anisometropia varied (P=0.009), with the lowest rate in Asians (2.7%) and highest in Hispanics (7.1%). Myopia >2.00 D was relatively uncommon (<2.0%) in all groups with the lowest rate in American Indians (0.2%) and highest rate in Asians (1.9%). Prevalence of astigmatism >1.50 D varied (P=0.01), with the lowest rate among American Indians (4.3%) and highest among Hispanics (11.1%).

CONCLUSIONS

Among Head Start preschool children, the prevalence of amblyopia and strabismus was similar among 5 racial/ethnic groups. Prevalence of significant refractive errors, specifically hyperopia, astigmatism, and anisometropia, varied by group, with the highest rate of hyperopia in non-Hispanic whites, and the highest rates of astigmatism and anisometropia in Hispanics.

Risk factors for strabismus and amblyopia in young Singapore Chinese children

PURPOSE

To determine the risk factors for strabismus and amblyopia in young Singapore Chinese children.

METHODS

A total of 3009 children were recruited for the population-based cross-sectional Strabismus, Amblyopia and Refractive Error in Singaporean Preschoolers Study (STARS). Strabismus was defined as any tropia identified on cover test. Visual acuity was measured in children aged 30-72 months with a logMAR chart where possible and the Sheridan-Gardiner test if not. Amblyopia was defined based on visual acuity and refractive error or presence of strabismus or past/present visual axis obstruction. Parents completed questionnaires on family, prenatal and birth histories.

RESULTS

Our study showed that 24 children aged 6-72 months (1.2%) had strabismus (20 with exotropia), and 20 children aged 30-72 months (0.8%) were amblyopic. After multivariate analysis, strabismus was associated with astigmatism ≥1.00 diopter (D; p = 0.03), amblyopia (p = 0.003), a sibling with strabismus (p < 0.001), and families with lower parental education (p = 0.04). In addition to strabismus, amblyopia was associated with anisometropia ≥1.00 D (p < 0.001) and astigmatism ≥1.00 D (p < 0.001). No association was noted between either strabismus or amblyopia and prematurity, maternal age or smoking.

CONCLUSION

This study highlights the importance of family history in strabismus, and the close associations between refractive error and strabismus with amblyopia. These factors play a more important role in young Singapore Chinese children.

Prevalence and etiology of amblyopia in Southern India: results from screening of school children aged 5-15 years

PURPOSE

To determine the prevalence and etiology of amblyopia in school children.

METHODS

A total of 4020 school children aged between 5 and 15 years were screened in a population-based, cross-sectional study. Best corrected visual acuity and detailed ophthalmic evaluation were performed in all participants. Amblyopia associated with degraded visual input due to high refractive error was labeled ametropic amblyopia. Anisometropic amblyopia was diagnosed in participants with interocular refractive error difference ≥1 diopter. Strabismic amblyopia included that due to conflicting visual inputs between the eyes due to squint. Stimulus deprivation amblyopia was defined as amblyopia due to obstruction of the visual axis.

RESULTS

Prevalence of amblyopia was 1.1% (n = 44). The number of boys with amblyopia (n = 25, 57%) was slightly higher than the number of girls with amblyopia (n = 19, 43%; p = 0.6). A total of 28 (63.7%) children had mild to moderate amblyopia, whereas 16 (36.3%) had severe amblyopia. Underlying amblyogenic causes were ametropia (50%), anisometropia (40.9%), strabismus (6.8%), visual deprivation (4.5%) and combined causes (2.2%). No statistically significant difference was noted in the prevalence of amblyopia between rural (1.2%) and urban (0.9%) children (p = 0.5).

CONCLUSION

In this study, the prevalence of amblyopia was 1.1% of the school children. Ametropia and anisometropia were the most common causes of amblyopia. We did not find any significant difference in amblyopia prevalence between rural and urban school children.

Prevalence, causes and associations of amblyopia in year 1 students in Central China : The Anyang childhood eye study (ACES)

BACKGROUND

Earlier diagnosis and treatment of amblyopia are associated with improved visual outcomes. This study reports the prevalence of amblyopia and associated factors in year 1 primary school students in central China.

METHODS

The school-based, cross-sectional study involved 3,112 year 1 primary school students . All the participants underwent a comprehensive eye examinations including cycloplegic refraction, cover test and ocular movement examinations. The unaided and best corrected visual acuity (BCVA) was recorded. Unilateral amblyopia was defined as a 2-line interocular difference with BCVA ≤ 20/32 (≥ logMar 0.2) in the worse eye and with coexisting anisometropia (≥ 1.00 D SE for hyperopia, ≥ 3.00 D SE for myopia, or ≥ 1.50 D for astigmatism), strabismus or past or present visual axis obstruction. Bilateral amblyopia was defined as BCVA in both eyes<20/40 (> logMar 0.3), with coexisting hyperopia ≥ 4 D SE, myopia ≤ -6 D SE, or astigmatism ≥ 2.5 D, or past or present visual axis obstruction.

RESULTS

Out of the 3,112 eligible students, 2,893 (93.0 %) students completed the examinations. The average age of the students was 7.1 ± 0.4 (mean ± standard deviation SD) years old. The prevalence of amblyopia was 1.0 % (95 % confidence interval [CI], 0.6 %-1.3 %) with no difference between the sexes (P = 0.88). Of the 27 amblyopic students, unilateral amblyopia was found in 18 (66.7 %) students, and bilateral amblyopia in 9 (33.3 %) students. Of 18 unilateral amblyopia, 13 were anisometropic amblyopia, 4 were strabismus amblyopia, 1 was mixed amblyopia. Of 9 bilateral amblyopia, 7 were isoametropic amblyopia, 2 were stimulus deprivation. The mean corrected VA of the amblyopic eyes was 30.50 logMAR letters (Snellen VA equivalent 4/12.6), and the range was 5 to 45 logMAR letters (Snellen VA equivalent 4/40-4/6.3). Most amblyopic eyes (38.9 %) were significantly hyperopic (spherical equivalent ≥ +3.00 D); 25.0 % were myopic. In addition, 58 (2.1 %) students had a previous amblyopia history of amblyopia that was not corroborated in this study.

CONCLUSIONS

The study shows a relatively low prevalence of amblyopia (1.0 %) in year 1 students in central China. Amblyopia is usually caused by abnormal refractive error.

Ocular problems in low-income and minority children

PURPOSE

To report the prevalence rates of screen failures for uncorrected refractive error, abnormal or excessive levels of hyperopia, problems in binocular vision, and deficiency of near point acuity as related to age and ethnicity in children.

METHODS

Vision screening tests were administered to 9,743 African-American, Hispanic, and white children aged 6 to 11 years in the Kansas City (United States) metropolitan area. Screening was performed by health professions students using HOTV charts for refractive errors, hyperopia, and near point acuity and a Random Dot E test for binocular vision. Children were screened in their elementary schools, located in primarily poor, urban neighborhoods. The main outcome measure was pass/fail outcomes from screenings, with confirmation of screen fails by licensed health care professionals.

RESULTS

For African-American children, 14.1% failed one or more vision screening tests. The corresponding screen failure rates for Hispanic and white children were 14.2% and 11.0%, respectively. There were significant differences in screening failure rates as a function of age and ethnicity, depending on the specific test. The highest rates of screen failures occurred in the 9 to 11 year old age range.

CONCLUSIONS

Vision screening failures were frequently associated with age and ethnicity. Screening performed by health professions students can successfully identify potential visual problems at rates similar to those reported in studies using more complex, sophisticated testing performed by specially trained individuals.

Risk factors for amblyopia in the vision in preschoolers study

OBJECTIVE

To evaluate risk factors for unilateral amblyopia and for bilateral amblyopia in the Vision in Preschoolers (VIP) study.

DESIGN

Multicenter, cross-sectional study.

PARTICIPANTS

Three- to 5-year-old Head Start preschoolers from 5 clinical centers, overrepresenting children with vision disorders.

METHODS

All children underwent comprehensive eye examinations, including threshold visual acuity (VA), cover testing, and cycloplegic retinoscopy, performed by VIP-certified optometrists and ophthalmologists who were experienced in providing care to children. Monocular threshold VA was tested using a single-surround HOTV letter protocol without correction, and retested with full cycloplegic correction when retest criteria were met. Unilateral amblyopia was defined as an interocular difference in best-corrected VA of 2 lines or more. Bilateral amblyopia was defined as best-corrected VA in each eye worse than 20/50 for 3-year-olds and worse than 20/40 for 4- to 5-year-olds.

MAIN OUTCOME MEASURES

Risk of amblyopia was summarized by the odds ratios and their 95% confidence intervals estimated from logistic regression models.

RESULTS

In this enriched sample of Head Start children (n = 3869), 296 children (7.7%) had unilateral amblyopia, and 144 children (3.7%) had bilateral amblyopia. Presence of strabismus (P<0.0001) and greater magnitude of significant refractive errors (myopia, hyperopia, astigmatism, and anisometropia; P<0.00001 for each) were associated independently with an increased risk of unilateral amblyopia. Presence of strabismus, hyperopia of 2.0 diopters (D) or more, astigmatism of 1.0 D or more, or anisometropia of 0.5 D or more were present in 91% of children with unilateral amblyopia. Greater magnitude of astigmatism (P<0.0001) and bilateral hyperopia (P<0.0001) were associated independently with increased risk of bilateral amblyopia. Bilateral hyperopia of 3.0 D or more or astigmatism of 1.0 D or more were present in 76% of children with bilateral amblyopia.

CONCLUSIONS

Strabismus and significant refractive errors were risk factors for unilateral amblyopia. Bilateral astigmatism and bilateral hyperopia were risk factors for bilateral amblyopia. Despite differences in selection of the study population, these results validated the findings from the Multi-Ethnic Pediatric Eye Disease Study and Baltimore Pediatric Eye Disease Study.

The plusoptiX S08 photoscreener as a vision screening tool for children with autism

PURPOSE

Children with autism and related disorders reportedly have an increased prevalence (40%) of ocular disorders, and comprehensive eye examinations by a pediatric ophthalmologist are recommended. Examinations can be very time consuming, expensive, and stressful for the child. A photoscreener such as the plusoptiX S08 may be a cost-effective, time-saving, and less invasive method for testing patients with autism. The purpose of this study was to determine the efficacy of photoscreening with the plusoptiX S08 in detecting amblyopia risk factors in children with autism.

METHODS

Photoscreening and complete ophthalmologic examinations were performed on 43 children with autism. Prevalence, sensitivity, specificity, positive predictive value, and negative predictive value were calculated using ophthalmologic examination as the gold standard.

RESULTS

The gold standard examination used American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee guidelines for the definition of amblyopia risk factors. The plusoptiX S08 referred 29 (67%) of 43 children. On examination, 16 patients (37%) had amblyopia risk factors. The plusoptiX S08 had a sensitivity of 94% (95% CI, 0.68-0.99). The specificity was 48% (95% CI, 0.29-0.68), the positive predictive value was 52% (95% CI, 0.33-0.70), and the negative predictive value was 93% (95% CI, 0.64-0.99).

CONCLUSIONS

The plusoptiX S08 is sensitive but less specific at detecting treatable ocular conditions in children with autism. The majority of children with autism and amblyopia risk factors were detected on screening; however, about half of all referrals had no amblyopia risk factors. The plusoptiX S08 reduced the need for a full examination in one-third of the children screened.

Identifying barriers to follow-up eye care for children after failed vision screening in a primary care setting

PURPOSE

To identify barriers to follow-up eye care in children who failed a visual acuity screening conducted by their primary care provider.

METHODS

Children aged 3-14 years who failed a visual acuity screening were identified. A phone survey with the parent of every child was conducted 4 months after the screening. Family demographics, parental awareness of childhood eye diseases and eye care for children, and barriers to follow-up eye care were assessed.

RESULTS

Of 971 children sampled, 199 (20.5%) failed a visual acuity screening. The survey was completed by the parents of 58 children (29.1%), of whom 27 (46.6%) presented for follow-up examination. The most common reason for failure to follow-up was parental unawareness of screening results (29.3%). Follow-up rates were higher in children with previous eye examinations than in those without (81% versus 17%; P = 0.005) and in children who waited <2 months for a follow-up appointment than in those who had to wait longer (100% versus 63%; P = 0.024). Child's sex, ethnicity, and health insurance status, parent's marital, education and employment status, household income, and transportation access were not associated with statistically significant different follow-up rates.

CONCLUSIONS

Parental unawareness of a failed visual acuity screening is an important barrier to obtaining follow-up. Strategies to improve follow-up rates after a failed visual acuity screening may include communicating the results clearly and consistently, providing education about the importance of timely follow-up, and offering logistic support for accessing eye appointments to families.

Why do only some hyperopes become strabismic?

Children with hyperopia greater than +3.5 diopters (D) are at increased risk for developing refractive esotropia. However, only approximately 20% of these hyperopes develop strabismus. This review provides a systematic theoretical analysis of the accommodation and vergence oculomotor systems with a view to understanding factors that could either protect a hyperopic individual or precipitate a strabismus. The goal is to consider factors that may predict refractive esotropia in an individual and therefore help identify the subset of hyperopes who are at the highest risk for this strabismus, warranting the most consideration in a preventive effort.

Amblyopia risk factor prevalence

PURPOSE

In 2003, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) published a set of risk factors for amblyopia. The intent was to promote uniformity of reporting and development in screening. Because this prevalence is not yet known, this meta-analysis is an attempt to estimate it.

METHODS

Major community preschool eye examination studies were reviewed and AAPOS cut-offs estimated.

RESULTS

The approximate prevalence of anisometropia is 1.2%, hyperopia is 6%, astigmatism is 15%, myopia is 0.6%, strabismus is 2.5%, and visual acuity less than 20/40 is 6%. The mean combined prevalence is 21% ± 2% compared to a prevalence of amblyopia 20/40 and worse of 2.5%.

CONCLUSIONS

Knowing risk factor prevalence simplifies validation efforts. Amblyopia screening with a risk factor sensitivity less than 100% is expected and desirable.

The relationship between anisometropia and amblyopia

This review aims to disentangle cause and effect in the relationship between anisometropia and amblyopia. Specifically, we examine the literature for evidence to support different possible developmental sequences that could ultimately lead to the presentation of both conditions. The prevalence of anisometropia is around 20% for an inter-ocular difference of 0.5D or greater in spherical equivalent refraction, falling to 2-3%, for an inter-ocular difference of 3D or above. Anisometropia prevalence is relatively high in the weeks following birth, in the teenage years coinciding with the onset of myopia and, most notably, in older adults starting after the onset of presbyopia. It has about one-third the prevalence of bilateral refractive errors of the same magnitude. Importantly, the prevalence of anisometropia is higher in highly ametropic groups, suggesting that emmetropization failures underlying ametropia and anisometropia may be similar. Amblyopia is present in 1-3% of humans and around one-half to two-thirds of amblyopes have anisometropia either alone or in combination with strabismus. The frequent co-existence of amblyopia and anisometropia at a child's first clinical examination promotes the belief that the anisometropia has caused the amblyopia, as has been demonstrated in animal models of the condition. In reviewing the human and monkey literature however it is clear that there are additional paths beyond this classic hypothesis to the co-occurrence of anisometropia and amblyopia. For example, after the emergence of amblyopia secondary to either deprivation or strabismus, anisometropia often follows. In cases of anisometropia with no apparent deprivation or strabismus, questions remain about the failure of the emmetropization mechanism that routinely eliminates infantile anisometropia. Also, the chronology of amblyopia development is poorly documented in cases of 'pure' anisometropic amblyopia. Although indirect, the therapeutic impact of refractive correction on anisometropic amblyopia provides strong support for the hypothesis that the anisometropia caused the amblyopia. Direct evidence for the aetiology of anisometropic amblyopia will require longitudinal tracking of at-risk infants, which poses numerous methodological and ethical challenges. However, if we are to prevent this condition, we must understand the factors that cause it to develop.

Prevalence of amblyopia or strabismus in asian and non-Hispanic white preschool children: multi-ethnic pediatric eye disease study

OBJECTIVE

To determine the age- and race-specific prevalence of amblyopia in Asian and non-Hispanic white children aged 30 to 72 months and of strabismus in children aged 6 to 72 months.

DESIGN

Cross-sectional survey.

PARTICIPANTS

A population-based, multiethnic sample of children aged 6 to 72 months was identified in Los Angeles and Riverside counties in California to evaluate the prevalence of ocular conditions.

METHODS

A comprehensive eye examination and in-clinic interview were conducted with 80% of eligible children. The examination included evaluation of ocular alignment, refractive error, and ocular structures in children aged 6 to 72 months, as well as a determination of optotype visual acuity (VA) in children aged 30 to 72 months.

MAIN OUTCOME MEASURES

The proportion of 6- to 72-month-old participants with strabismus and 30- to 72-month-olds with optotype VA deficits and amblyopia risk factors consistent with study definitions of amblyopia.

RESULTS

Strabismus was found in 3.55% (95% confidence interval [CI], 2.68-4.60) of Asian children and 3.24% (95% CI, 2.40-4.26) of non-Hispanic white children, with a higher prevalence with each subsequent older age category from 6 to 72 months in both racial/ethnic groups (P=0.0003 and 0.02, respectively). Amblyopia was detected in 1.81% (95% CI, 1.06-2.89) of Asian and non-Hispanic white children; the prevalence of amblyopia was higher for each subsequent older age category among non-Hispanic white children (P=0.01) but showed no significant trend among Asian children (P=0.30).

CONCLUSIONS

The prevalence of strabismus was similar in Asian and non-Hispanic white children and was found to be higher among older children from 6 to 72 months. The prevalence of amblyopia was the same in Asian and non-Hispanic white children; prevalence seemed to be higher among older non-Hispanic white children but was relatively stable by age in Asian children. These findings may help clinicians to better understand the patterns of strabismus and amblyopia and potentially inform planning for preschool vision screening programs.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Strabismus in craniosynostosis

Strabismus is common in craniosynostosis, with rates from 39% to 90.9% in Crouzon, Apert, Pfeiffer, and Saethre-Chotzen syndromes. This article reviews the epidemiology of strabismus in these disorders and discusses competing theories of the mechanism, including absent muscles, excyclorotation of muscles, and instability of muscle pulleys. The authors then review options for surgical treatment of the often complex ocular misalignment in these disorders.

Preschool vision screening in primary care pediatric practice

OBJECTIVES

We determined the efficacy of pediatric-based preschool vision screening, as knowledge of vision screening effectiveness in primary care pediatrics is incomplete.

METHODS

Pediatricians and staff at nine primary care pediatric practices were trained in vision screening, and practices screened children aged 3-5 years from May 2007 through July 2008. Children failing or considered untestable were referred for pediatric ophthalmology examinations. We determined rates of testability, failure, referral, and ophthalmologic examination completion, as well as positive predictive values (PPVs) of screening failure and untestability. We also surveyed practices to assess the ease and accuracy of preschool vision screening.

RESULTS

Of 2,933 children screened, 93 (3.2%) failed the vision screening and 349 (11.9%) were untestable. Untestability was highest (27.1%) among 3-year-olds. The PPV for failing any aspect of the vision screening was 66.7%; for children aged 3, 4, and 5 years, the PPVs for failing were 30.0%, 77.8%, and 87.5%, respectively. However, only 38.7% of children who failed the vision screening received ophthalmologic examinations, despite multiple follow-up attempts. Pediatricians rated the ease and accuracy of screening 3-year-old children lower than for screening older children.

CONCLUSIONS

Visual acuity-based screening had good PPV for vision loss for 4- and 5-year-old children but was less successful for 3-year-olds. Rates of referral and ophthalmologic examination completion were low, especially among children from low-income families.

Exploring pre-school vision screening in primary care offices in Alabama

PURPOSE

To investigate practices, barriers, and facilitators of universal pre-school vision screening (PVS) at pediatric primary care offices.

METHODS

Focus group sessions (FGS) were moderated on-site at nine pediatric practices. A semi-structured topic guide was used to standardize and facilitate FGS. Discussions were audiotaped, and transcriptions were used to develop themes. All authors reviewed and agreed on the resultant themes.

RESULTS

FGS included 13 physicians and 32 nurses/certified medical assistants (CMAs), of whom 82% personally conducted some facet of PVS. In all practices, nurses/CMAs tested visual acuity (most using a non-recommended test), and physicians completed vision screening with external observation, fix/follow, red reflex, and cover test. Facilitators included (1) accepting that PVS is a routine part of the well-child visit, and (2) using an electronic medical record with prompts to record acuity (eight of nine practices). Barriers were related to difficulty testing pre-schoolers, distractions in the office setting, time constraints, and limited reimbursement.

CONCLUSIONS

Responsibility for PVS is shared by physicians and nurses/CMAs; thus, interventions to improve PVS should target both. Few practices are aware of new evidence-based PVS tests; thus, active translational efforts are needed to change current primary care practices.

Amblyopia and binocular vision

Amblyopia is the most common cause of monocular visual loss in children, affecting 1.3%-3.6% of children. Current treatments are effective in reducing the visual acuity deficit but many amblyopic individuals are left with residual visual acuity deficits, ocular motor abnormalities, deficient fine motor skills, and risk for recurrent amblyopia. Using a combination of psychophysical, electrophysiological, imaging, risk factor analysis, and fine motor skill assessment, the primary role of binocular dysfunction in the genesis of amblyopia and the constellation of visual and motor deficits that accompany the visual acuity deficit has been identified. These findings motivated us to evaluate a new, binocular approach to amblyopia treatment with the goals of reducing or eliminating residual and recurrent amblyopia and of improving the deficient ocular motor function and fine motor skills that accompany amblyopia.

Guidelines for automated preschool vision screening: a 10-year, evidence-based update

In 2003 the American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee proposed criteria for automated preschool vision screening. Recent literature from epidemiologic and natural history studies, randomized controlled trials of amblyopia treatment, and field studies of screening technologies have been reviewed for the purpose of updating these criteria. The prevalence of amblyopia risk factors (ARF) is greater than previously suspected; many young children with low-magnitude ARFs do not develop amblyopia, and those who do often respond to spectacles alone. High-magnitude ARFs increase the likelihood of amblyopia. Although depth increases with age, amblyopia remains treatable until 60 months, with decline in treatment effectiveness after age 5. US Preventive Services Task Force Preventative Services Task Force guidelines allow photoscreening for children older than 36 months of age. Some technologies directly detect amblyopia rather than ARFs. Age-based criteria for ARF detection using photoscreening is prudent: referral criteria for such instruments should produce high specificity for ARF detection in young children and high sensitivity to detect amblyopia in older children. Refractive screening for ARFs for children aged 12-30 months should detect astigmatism >2.0 D, hyperopia >4.5 D, and anisometropia >2.5 D; for children aged 31-48 months, astigmatism >2.0 D, hyperopia > 4.0 D, and anisometropia >2.0 D. For children >49 months of age original criteria should be used: astigmatism >1.5 D, anisometropia>1.5 D, and hyperopia >3.5 D. Visually significant media opacities and manifest (not intermittent) strabismus should be detected at all ages. Instruments that detect amblyopia should report results using amblyopia presence as the gold standard. These new American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee guidelines will improve reporting of results and comparison of technologies.

The measurement and treatment of suppression in amblyopia

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current estimates put the prevalence of amblyopia at approximately 1-3%^1-3, the majority of cases being monocular². Amblyopia is most frequently caused by ocular misalignment (strabismus), blur induced by unequal refractive error (anisometropia), and in some cases by form deprivation.

Although amblyopia is initially caused by abnormal visual input in infancy, once established, the visual deficit often remains when normal visual input has been restored using surgery and/or refractive correction. This is because amblyopia is the result of abnormal visual cortex development rather than a problem with the amblyopic eye itself^4,5 . Amblyopia is characterized by both monocular and binocular deficits^6,7 which include impaired visual acuity and poor or absent stereopsis respectively. The visual dysfunction in amblyopia is often associated with a strong suppression of the inputs from the amblyopic eye under binocular viewing conditions⁸. Recent work has indicated that suppression may play a central role in both the monocular and binocular deficits associated with amblyopia^9,10 .

Current clinical tests for suppression tend to verify the presence or absence of suppression rather than giving a quantitative measurement of the degree of suppression. Here we describe a technique for measuring amblyopic suppression with a compact, portable device^11,12 . The device consists of a laptop computer connected to a pair of virtual reality goggles. The novelty of the technique lies in the way we present visual stimuli to measure suppression. Stimuli are shown to the amblyopic eye at high contrast while the contrast of the stimuli shown to the non-amblyopic eye are varied. Patients perform a simple signal/noise task that allows for a precise measurement of the strength of excitatory binocular interactions. The contrast offset at which neither eye has a performance advantage is a measure of the "balance point" and is a direct measure of suppression. This technique has been validated psychophysically both in control^13,14 and patient^6,9,11 populations.

In addition to measuring suppression this technique also forms the basis of a novel form of treatment to decrease suppression over time and improve binocular and often monocular function in adult patients with amblyopia^12,15,16 . This new treatment approach can be deployed either on the goggle system described above or on a specially modified iPod touch device¹⁵.

Associations of anisometropia with unilateral amblyopia, interocular acuity difference, and stereoacuity in preschoolers

PURPOSE

To evaluate the relationship of anisometropia with unilateral amblyopia, interocular acuity difference (IAD), and stereoacuity among Head Start preschoolers using both clinical notation and vector notation analyses.

DESIGN

Multicenter, cross-sectional study.

PARTICIPANTS

Three- to 5-year-old participants in the Vision in Preschoolers (VIP) study (n = 4040).

METHODS

Secondary analysis of VIP data from participants who underwent comprehensive eye examinations, including monocular visual acuity testing, stereoacuity testing, and cycloplegic refraction. Visual acuity was retested with full cycloplegic correction when retest criteria were met. Unilateral amblyopia was defined as IAD of 2 lines or more in logarithm of the minimum angle of resolution (logMAR) units. Anisometropia was defined as a 0.25-diopter (D) or more difference in spherical equivalent (SE) or in cylinder power and 2 approaches using power vector notation. The percentage with unilateral amblyopia, mean IAD, and mean stereoacuity were compared between anisometropic and isometropic children.

MAIN OUTCOMES MEASURES

The percentage with unilateral amblyopia, mean IAD, and mean stereoacuity.

RESULTS

Compared with isometropic children, anisometropic children had a higher percentage of unilateral amblyopia (8% vs. 2%), larger mean IAD (0.07 vs. 0.05 logMAR), and worse mean stereoacuity (145 vs. 117 arc sec; all P<0.0001). Larger amounts of anisometropia were associated with higher percentages of unilateral amblyopia, larger IAD, and worse stereoacuity (P<0.001 for trend). The percentage of unilateral amblyopia increased significantly with SE anisometropia of more than 0.5 D, cylindrical anisometropia of more than 0.25 D, vertical and horizontal meridian (J0) or oblique meridian (J45) of more than 0.125 D, or vector dioptric distance of more than 0.35 D (all P<0.001). Vector dioptric distance had greater ability to detect unilateral amblyopia than cylinder, SE, J0, or J45 (P<0.001).

CONCLUSIONS

The presence and amount of anisometropia were associated with the presence of unilateral amblyopia, larger IAD, and worse stereoacuity. The threshold level of anisometropia at which unilateral amblyopia became significant was lower than current guidelines. Vector dioptric distance is more accurate than spherical equivalent anisometropia or cylindrical anisometropia in identifying preschoolers with unilateral amblyopia.

Development of educational materials to improve rates of early eye care for Hispanic children

The purpose of this study was to develop targeted materials to encourage Hispanic parents to seek eye care for their children. Hispanic children present with high rates of eye problems such as astigmatism, strabismus, and amblyopia. Related vision impairment can be prevented with timely detection and treatment. After failing a vision screening, a child must obtain professional eye care to take care of the suspected problem. We involved Hispanic community members and health care experts in Alabama to develop educational materials to encourage Hispanic parents to seek eye care for their children. There were six stages in the development of the educational materials: (a) focus groups with Hispanic parents, (b) development of preliminary materials (c) panel with Hispanic health experts (d) panel with members of the target population (e) final production of materials (f) pilot testing of materials. The parents and health experts suggested the information should be provided in the form of radio announcements, brochures, and newspaper advertisements. They also noted the content should stress the importance of seeking vision care for children even when there were no visible problems. Materials developed through this project included messages designed to overcome specific barriers identified by Hispanic parents and to educate them on the importance of comprehensive eye care for all children, regardless of the presence of visible symptoms.

Factors associated with strabismus in spina bifida myelomeningocele

PURPOSE

Higher prevalence of strabismus in individuals with spina bifida myelomeningocele (SBM) has previously been attributed to hydrocephalus; however, SBM is associated with many other complications. This study investigates the relation between strabismus and other factors in SBM.

METHODS

Children aged 3 to 18 years with SBM (n = 112) received an eye examination including assessment of ocular alignment by cover or Hirschberg test. Gestational age, respiratory distress at birth, birth weight, maternal age at birth, number of shunt revisions, and spinal lesion level were also obtained. The relation between these factors and strabismus was analyzed.

RESULTS

Forty-two participants had strabismus. Maternal age (P = .4) and respiratory distress (P = .6) were not significantly related to strabismus. Lower birth weight was suggestive of a relation with strabismus (logistic regression, P = .05) and younger gestational age was related to strabismus (logistic regression, P = .01). Participants who had at least one shunt revision were more likely to have strabismus (Fisher's exact test, P = .038). Spinal lesion level was significantly related to strabismus with increased likelihood of strabismus for spinal lesions closer to the brain (Wald chi-square, 1,100 = 4.29, P = .038).

CONCLUSION

These findings indicate that several factors are associated with strabismus in SBM. Some of these factors (lower birth weight and younger gestational age) are associated with strabismus in the general population, whereas the association of strabismus and level of spinal lesion may be unique to SBM and may be related to the more severe brain dysmorphology associated with upper level spinal lesions.

Horizontal strabismus worldwide--what are the risk factors?

Horizontal strabismus has constant risk factors of ethnicity, family history, genetic conditions and potentially modifiable risk factors of maternal smoking, prematurity, low birth weight, refractive errors and neurodisability.

Anisometropia in children from infancy to 15 years

PURPOSE

To investigate anisometropia in children from age 6 months to 15 years.

METHODS

Children with refractions at 6 months (n = 1120), 5 years (n = 395), and 12 to 15 years (n = 312) were included in this study. All children were refracted in the laboratory by noncycloplegic retinoscopy. Myopes had spherical equivalent refraction (SER) of the less ametropic eye of less than -0.50 D, hyperopes had SER of the less ametropic eye greater than or equal to 1.00 D, and emmetropes had SER of the less ametropic eye from -0.50 to +1.00 D.

RESULTS

The mean difference in refraction between the two eyes was similar at 6 months (0.11 D) and 5 years (0.15 D), increasing to 0.28 D at 12 to 15 years. Using a cutoff of 1.00 D SER for anisometropia, the prevalence was 1.96%, 1.27%, and 5.77% at 6 months, 5 years, and 12 to 15 years, respectively. At 12 to 15 years, the prevalence of anisometropia in the myopes was 9.64% and in the hyperopes was 13.64%, both significantly higher than that in the emmetropes (3.38%, P < 0.05). The degree of anisometropia at 12 to 15 years was significantly associated with the refractive error of the less ametropic eye at 12 to 15 years, with and without adjustment for relevant covariates (P < 0.05). Infants with significant astigmatism (cylinder power ≥ 1.00 D in one or both eyes) have an increased risk of anisometropia (P < 0.05).

CONCLUSIONS

The prevalence of anisometropia increases between 5 and 15 years, when some children's eyes grow longer and become myopic. However, anisometropia was found to accompany both myopia and hyperopia, suggesting that other mechanisms in addition to excessive eye growth may exist for anisometropia development, especially in hyperopia.

Pharmacological enhancement of treatment for amblyopia

Background

The purpose of this study was to compare a weight-adjusted dose of carbidopa- levodopa as treatment adjunctive to occlusion therapy with occlusion therapy alone in children and adults with different types of amblyopia.

Methods

This prospective study included 63 patients with amblyopia classified into two groups, ie, an occlusion group which included 35 patients who received occlusion therapy only and a pharmacological enhancement group which included 28 patients who received oral carbidopa-levodopa together with occlusion therapy for 6 weeks.

Results

The mean logarithm of the minimal angle of resolution (logMAR) of the eyes with amblyopia was not significantly different in the occlusion group (0.52, 0.52, and 0.51) than in the pharmacological enhancement group (0.58, 0.49, and 0.56) at three follow-up visits (at months 1, 3, and 12, respectively). There was a highly significant improvement in mean logMAR of amblyopic eyes compared with baseline in both occlusion groups (from 0.68 to 0.52, from 0.68 to 0.52, and from 0.68 to 0.51) and in the pharmacological enhancement group (from 0.81 to 0.58, from 0.81 to 0.49, and from 0.81 to 0.56) at the month 1, 3, and 12 visits (P = 0.01, P = 0.01, and P = 0.001, respectively). The improvement of mean logMAR in the subgroup of patients older than 12 years was greater in the pharmacological enhancement group (42.5%) than in the occlusion group (30%). The improvement of mean logMAR in the subgroup of patients with severe amblyopia was greater in the pharmacological enhancement group (34.3%) than in the occlusion group (22%).

Conclusion

Significant improvement was reported in both groups at all follow-up visits over 1 year. Regardless of the etiology of amblyopia, levodopa-carbidopa may be added to part-time occlusion in older patients as a means of increasing the plasticity of the visual cortex. Levodopa may add to the effect of occlusion in severe amblyopia and bilateral amblyopia.

Validation and cost-effectiveness of a home-based screening system for amblyopia

PURPOSE

To investigate the cost-effectiveness of a novel home-based screening system for amblyopia and amblyogenic risk factors.

DESIGN

Evaluation of diagnostic test or technology.

PARTICIPANTS

Two thousand four hundred forty-two preschoolers 3 to 6 years of age from 10 kindergartens randomly selected from Guangzhou participated in the study in 2009.

METHODS

Preschoolers were assessed for amblyopia and amblyogenic risk factors by their parents using the home-based screening system and were re-evaluated by professionals who conducted a comprehensive eye examination.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive predictive value, negative predictive value, and the cost-benefit of the home-based screening system were calculated by comparing the results from the home-assessed model and those from the professional evaluation.

RESULTS

Three thousand three hundred children were invited to participate in the study, and 2308 (1216 boys and 1092 girls) completed all of the procedures. Twenty-four amblyopes were found by professional examinations. Fifteen of these amblyopes had not been diagnosed previously, and 12 of them were detected by the home-assessment model. The sensitivity, specificity, positive predictive value, and negative predictive value were 80.0%, 94.1%, 8.2%, and 99.9%, respectively. Professional examinations cost an average of US $1131.00 per case of amblyopia detected, whereas the cost was only US $266.00 per case for the home-based method. For amblyogenic factors, 50, 87, and 96 children were classified into grade I, II, or III according to the professional examinations. The corresponding numbers in the home-based system were 23, 29, and 15, respectively. Accordingly, the true positive rates were 46.0%, 33.3%, and 15.6% for each grade.

CONCLUSIONS

The home-based amblyopia screening system was found to be a simple, effective, and cost-beneficial method for amblyopia screening and amblyogenic risk factors. The approach offers a practical option for developing areas with large populations.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Causes of blindness and visual impairment in Latin America

We review what is known in each country of the Latin American region with regards to blindness and visual impairment and make some comparisons to Hispanic populations in the United States. Prevalence of blindness varied from 1.1% in Argentina to 4.1% in Guatemala in people 50 years of age and older, with the major cause being cataract. Diabetic retinopathy and glaucoma are starting to make serious inroads, although epidemiological data are limited, and age-related macular degeneration is now a concern in some populations. Infectious diseases such as trachoma and onchocerciasis are quickly diminishing. Although progress has been made, retinopathy of prematurity remains the major cause of childhood blindness. If VISION 2020 is to succeed, many more epidemiological studies will be needed to set priorities, although some can be of the Rapid Assessment of Avoidable Blindness design. Developing the infrastructure for screening and treatment of ophthalmic disease in Latin America continues to be a challenge.

Can perceptual learning be used to treat amblyopia beyond the critical period of visual development?

BACKGROUND

Amblyopia presents early in childhood and affects approximately 3% of western populations. The monocular visual acuity loss is conventionally treated during the 'critical periods' of visual development by occluding or penalising the fellow eye to encourage use of the amblyopic eye. Despite the measurable success of this approach in many children, substantial numbers of people still suffer with amblyopia later in life because either they were never diagnosed in childhood, did not respond to the original treatment, the amblyopia was only partially remediated, or their acuity loss returned after cessation of treatment.

PURPOSE

In this review, we consider whether the visual deficits of this largely overlooked amblyopic group are amenable to conventional and innovative therapeutic interventions later in life, well beyond the age at which treatment is thought to be effective.

RECENT FINDINGS

There is a considerable body of evidence that residual plasticity is present in the adult visual brain and this can be harnessed to improve function in adults with amblyopia. Perceptual training protocols have been developed to optimise visual gains in this clinical population. Results thus far are extremely encouraging; marked visual improvements have been demonstrated, the perceptual benefits transfer to new visual tasks and appear to be relatively enduring. The essential ingredients of perceptual training protocols are being incorporated into video game formats, facilitating home-based interventions.

SUMMARY

Many studies support perceptual training as a tool for improving vision in amblyopes beyond the critical period. Should this novel form of treatment stand up to the scrutiny of a randomised controlled trial, clinicians may need to re-evaluate their therapeutic approach to adults with amblyopia.

Functional magnetic resonance imaging of binocular interactions in visual cortex in strabismus

PURPOSE

To observe changes in primary visual cortical activation associated with perceptual suppression in individuals with strabismus, using functional magnetic resonance imaging (fMRI).

METHODS

In Phase 1, pilot data were collected from 1 control and 8 strabismic participants, including 5 with amblyopia. In Phase 2, results were collected from 7 participants with strabismus (2 recalled and 5 new), including 2 with amblyopia. fMRI compared primary visual cortex activation in two conditions: visual stimuli presented to both eyes, to evoke perceptual suppression of one eye in individuals with strabismus, and visual stimulation presented only to one eye.

RESULTS

Visual cortical activity modulations positively correlated with perceptual suppression were seen in 3 of 5 non-amblyopic Phase 2 study participants, but not in amblyopic subjects.

CONCLUSION

Cortical activity modulations correlated with modulation of strabismic suppression are detectable in non-amblyopic individuals using fMRI, suggesting a neural basis for strabismic suppression in primary visual cortex.

Vision and the achievement gap among urban minority youth

OBJECTIVES

To outline the prevalence and disparities of vision problems among school-aged urban minority youth, causal pathways through which vision problems adversely affects academic achievement, and proven or promising approaches for schools to address these problems.

METHODS

Literature review.

RESULTS

More than 20% of school-aged youth have some kind of vision problem. In a nationally representative sample of more than 48,000 youth under age 18, those from lower income families were less likely to have diagnosed eye conditions than White children and children living in higher income families. When diagnosed with eye care problems, Black youth living in poverty received fewer and less intensive services. Causal pathways through which vision problems adversely affect academic achievement include sensory perceptions, cognition, and school connectedness. Vision screening is widespread in the nation's schools, but the educational (and public health) benefits from these efforts are jeopardized by lack of follow-up and coordination of efforts.

CONCLUSIONS

Vision problems are highly and disproportionately prevalent among school-aged urban minority youth, have a negative impact on academic achievement through their effects on sensory perceptions, cognition, and school connectedness, and effective practices are available for schools to address these problems. School-based vision screening programs are a logical approach for the early detection and treatment of vision problems affecting youth and are widely implemented in the nation's schools. To more fully realize the educational (and public health) benefits of current investments in screening, programs will require improved follow-up and coordination between and among agencies conducting screening, school nurses, teachers and parents, and in some cases community resources.

Efficacy of a web-based intervention to improve and sustain knowledge and screening for amblyopia in primary care settings

PURPOSE

To evaluate the efficacy of a physician-targeted website to improve knowledge and self-reported behavior relevant to strabismus and amblyopia ("vision") in primary care settings.

METHODS

Eligible providers (filing Medicaid claims for at least eight well-child checks at ages 3 or 4 years, 1 year before study enrollment), randomly assigned to control (chlamydia and blood pressure) or vision groups, accessed four web-based educational modules, programmed to present interactive case vignettes with embedded questions and feedback. Each correct response, assigned a value of +1 to a maximum of +7, was used to calculate a summary score per provider. Responses from intervention providers (IPs) at baseline and two follow-up points were compared to responses to vision questions, taken at the end of the study, from control providers (CPs).

RESULTS

Most IPs (57/65) responded at baseline and after the short delay (within 1 hour after baseline for 38 IPs). A subgroup (27 IPs and 42 CPs) completed all vision questions after a long delay averaging 1.8 years. Scores from IPs improved after the short delay (median score, 3 vs. 6; P = 0.0065). Compared to CPs, scores from IPs were similar at baseline (P = 0.6473) and higher after the short-term (P < 0.0001) and long-term (P < 0.05) delay.

CONCLUSIONS

Significant improvements after the short delay demonstrate the efficacy of the website and the potential for accessible, standardized vision education. Although improvements subsided over time, the IPs' scores did not return to baseline levels and were significantly better compared to CPs tested 1 to 3 years later.

Risk factors for decreased visual acuity in preschool children: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies

OBJECTIVE

To investigate risk factors associated with unilateral or bilateral decreased visual acuity (VA) in preschool children.

DESIGN

Population-based, cross-sectional prevalence study.

PARTICIPANTS

Population-based samples of 6504 children ages 30 to 72 months from California and Maryland.

METHODS

Participants were preschool African-American, Hispanic, and non-Hispanic white children from Los Angeles, California, and Baltimore, Maryland. Data were obtained by a parental interview and a detailed ocular examination. Logistic regression models were used to evaluate the independent associations between demographic, behavioral, and clinical risk factors with unilateral and bilateral decreased VA.

MAIN OUTCOME MEASURES

Odds ratios (ORs) for various risk factors associated with interocular difference (IOD) in VA of ≥2 lines with ≤20/32 in the worse eye, or bilateral decreased VA <20/40 or <20/50 if <48 months of age.

RESULTS

In multivariate logistic regression analysis, 2-line IOD with a VA of ≤20/32 was independently associated with Hispanic ethnicity (OR, 2.05), esotropia (OR, 8.98), spherical equivalent (SE) anisometropia (ORs ranging between 1.5 and 39.7 for SE anisometropia ranging between 0.50 to <1.00 diopters [D] and ≥2.00 D), and aniso-astigmatism in J0 or J45 (ORs ranging between 1.4 and ≥5.3 for J0 or J45 differences ranging between 0.25 to <0.50 D and ≥1.00 D). Bilateral decreased VA was independently associated with lack of health insurance (OR, 2.9), lower primary caregiver education (OR, 1.7), astigmatism (OR, 2.3 and 17.6 for astigmatism 1.00 to <2.00 D and ≥2.00 D), and SE hyperopia ≥4.00 D (OR, 10.8).

CONCLUSIONS

Anisometropia and esotropia are risk factors for IOD in VA. Astigmatism and high hyperopia are risk factors for bilateral decreased VA. Guidelines for the screening and management of decreased VA in preschool children should be considered in light of these risk associations.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Risk factors for hyperopia and myopia in preschool children the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies

PURPOSE

To describe the risk factors associated with hyperopia and myopia among children 6 to 72 months of age.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

Population-based samples of 9970 children 6 to 72 months of age from Los Angeles County, California, and Baltimore, Maryland.

METHODS

Participants were preschool African-American, Hispanic, and non-Hispanic white children (n = 9770) from Los Angeles, California, and Baltimore, Maryland. Parental questionnaires and a comprehensive eye examination were administered. Demographic, behavioral, and clinical risk factors associated with hyperopia (≥2.00 diopters [D]) and myopia (≤-1.00 D) were determined.

MAIN OUTCOME MEASURES

Odds ratios (ORs) for risk factors associated with myopia and hyperopia.

RESULTS

Compared with non-Hispanic whites, African-American (OR, 6.0) and Hispanic (OR, 3.2) children were more likely to be myopic. Children 6 to 35 months of age were more likely to be myopic compared with those 60 to 72 months of age (OR, ≥1.7). Compared with African-American children, non-Hispanic white (OR, 1.63) and Hispanic (OR, 1.49) children were more likely to be hyperopic. Children whose parents had health insurance (OR, 1.5) and those with a history of maternal smoking during pregnancy (OR, 1.4) were more likely to have hyperopia. Astigmatism of 1.5 D or more at any axis was associated with myopia (OR, 4.37) and hyperopia (OR, 1.43).

CONCLUSIONS

Children in specific racial or ethnic groups and age groups are at higher risk of having myopia and hyperopia. Cessation of maternal smoking during pregnancy may reduce the risk of hyperopia in these children. Given that both myopia and hyperopia are risk factors for the development of amblyopia and strabismus, these risk factors should be considered when developing guidelines for screening and intervention in preschool children.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Risk factors associated with childhood strabismus: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies

OBJECTIVE

To investigate risk factors associated with esotropia or exotropia in infants and young children.

DESIGN

Population-based cross-sectional prevalence study.

PARTICIPANTS

Population-based samples of 9970 children 6 to 72 months of age from California and Maryland.

METHODS

Participants were preschool African-American, Hispanic, and non-Hispanic white children participating in the Multi-Ethnic Pediatric Eye Disease Study and the Baltimore Eye Disease Study. Data were obtained by parental interview and ocular examination. Odd ratios and 95% confidence intervals were calculated to evaluate the association of demographic, behavioral, and clinical risk factors with esotropia and exotropia.

MAIN OUTCOME MEASURES

Odds ratios (ORs) for various risk factors associated with esotropia or exotropia diagnosis based on cover testing.

RESULTS

In multivariate logistic regression analysis, esotropia was associated independently with prematurity, maternal smoking during pregnancy, older preschool age (48-72 months), anisometropia, and hyperopia. There was a severity-dependent association of hyperopia with the prevalence of esotropia, with ORs increasing from 6.4 for 2.00 diopters (D) to less than 3.00 D of hyperopia, to 122.0 for 5.00 D or more of hyperopia. Exotropia was associated with prematurity, maternal smoking during pregnancy, family history of strabismus, female sex, astigmatism (OR, 2.5 for 1.50 to <2.50 D of astigmatism, and 5.9 for ≥2.5 D of astigmatism), and anisoastigmatism in the J0 component (OR, ≥2 for J0 anisoastigmatism of ≥0.25 D).

CONCLUSIONS

Prematurity and maternal smoking during pregnancy are associated with a higher risk of having esotropia and exotropia. Refractive error is associated in a severity-dependent manner to the prevalence of esotropia and exotropia. Because refractive error is correctable, these risk associations should be considered when developing guidelines for the screening and management of refractive error in infants and young children.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Trends in surgical correction of strabismus: a 20-year experience, 1990-2009

BACKGROUND

Recent reports and anecdotal observations suggest that strabismus surgery, particularly for infantile esotropia, may be in decline, although a recent population-based study found the incidence to be stable.

METHODS

We analyzed the surgical database of 4,494 primary pediatric strabismus procedures from 1990 through 2009 at Children's Medical Center of Dallas. Linear regression models were used to identify the relationship between the year and the proportion of each surgical category (infantile esotropia, all esotropia, exotropia, and other) using the least-squares approach.

RESULTS

Surgery for infantile esotropia (mean age, 10 months) was performed on 374 patients (mean, 19; range, 11-27/year). Trend analysis demonstrated no significant change in the annual rate of surgery for infantile esotropia (R(2) = 0.004) during the 20-year study period. Additionally, when compared to the annual number of births in Dallas County, no significant change in the incidence of surgically corrected infantile esotropia was noted during the study period (P = 0.25); however, surgery for both infantile esotropia (P = 0.001) and for any esotropia (P = 0.002) declined, while surgery for exotropia increased (P = 0.002) as a proportion of all primary strabismus surgeries.

CONCLUSIONS

The incidence of surgically corrected infantile esotropia has remained stable over a 20-year period. As a proportion of all primary strabismus procedures, surgery for all types of esotropia has decreased and for exotropia has increased.