Preschool vision screening in a Swedish city region: results after alteration of criteria for referral to eye clinics

The Swedish National Pediatric Cataract Register (PECARE): incidence and onset of postoperative glaucoma

PURPOSE

The aim was to report cumulative incidence and time of onset of postoperative glaucoma in a paediatric early cataract surgery cohort.

METHODS

Data were retrieved from the Pediatric Cataract Register (PECARE), a prospective register of Swedish cataract operations before 8 years of age. All eyes with surgery between January 2007 and December 2014 and a registered follow-up were included. Cataracts caused by uveitis, trauma or coexisting congenital glaucoma were excluded. Glaucoma was defined as early onset if diagnosed within a year after surgery and late onset if diagnosed later.

RESULTS

The study included 288 eyes in 207 children (106 girls), 81 with bilateral and 126 with unilateral cataracts, with a mean follow-up of 3.31 ± 1.77 years. Of the 288, 168 (58.3%) had surgery before 3 months of age; most of these 92.3% (155/168) were defined as dense, 208 (72.2%) were below 1 year of age. Cumulative incidence of surgically treated glaucoma among individuals was 23.7% (49/207). Median time to glaucoma onset was 0.91 years (range: 0.05-4.97 years) for eyes. Early-onset glaucoma was found in 98 % (63/64), and late onset in 2% (1/64).

CONCLUSION

In this paediatric cataract cohort, a majority of eyes had surgery before 3 months of age (58.3%). Secondary glaucoma-onset peaked within the first postoperative year, with a cumulative incidence of 23.7%. Surgery performed after the first month of life, resulted in a lower glaucoma rate. Long-term follow-up will reveal whether the low rate of late-onset glaucoma with early surgery will last, and if so, the consequences.

The impact of vision screening in preschool children on visual function in the Swedish adult population

BACKGROUND

Amblyopia is the most common monocular visual impairment in Scandinavia. A visual screening programme for preschool children was introduced in Sweden in the 1970s to reduce the prevalence of amblyopia. The purpose of this study was to investigate the impact of this visual screening programme in adult men recruited to the armed forces in Sweden.

METHODS

The prevalence of amblyopia was compared in recruits born in 1956-1957 (n = 1500), before the introduction of the visual screening programme (unscreened), and those born in 1977-1979 (n = 2626), after the visual screening programme was introduced (screened). Amblyopia was defined as bilateral, if the bilateral best corrected visual acuity (BCVA) was <0.5 (20/40), and unilateral if there was a ≥2-line interocular difference and BCVA was <0.625 (20/32) in the worse eye. Subgroup analysis was performed on recruits with hyperopia, myopia and anisometropia.

RESULTS

The prevalence of amblyopia was significantly lower after the introduction of the Swedish visual screening programme. Forty-seven (3.3%) of the unscreened and 23 (0.9%) of the screened recruits had unilateral amblyopia (p < 0.0001, OR = 0.26 (95%CI 0.16-0.43)). The risk for developing amblyopia was markedly reduced by screening in recruits with hyperopia (≥2D) (p < 0.0001 and OR 0.034 (95% CI 0.003-0.207)) and anisometropia (≥1.5D interocular difference) (p < 0.01 and OR 0.20 (95% CI 0.08-0.66)). Only a few recruits with myopia had amblyopia.

CONCLUSIONS

The results demonstrate the value of the Swedish visual screening programme for preschool children in preventing amblyopia. Anisometropia or high hyperopic refractive errors can be identified by screening and corrected to prevent amblyopia.

Analysis of the current preschool vision screening in Denmark

PURPOSE

To analyse the current vision screening programme for children attending school with respect to identifying children with significant refractive errors.

METHODS

A total of 950 children from the municipality of Roskilde, Denmark, were invited to participate in a cross-sectional study of vision screening. 447 children aged 4.5-7 years participated in the study. The children completed a vision screening and a full eye examination. The vision screening consisted of visual acuity at distance (VA), visual acuity at distance with +2.0 glasses (VA+2), visual acuity at near (VAnear) and Lang II stereotest. A LogMAR-based picture chart was used for the vision testing. Significant refractive errors were defined as hyperopia ≥+3.5 D, myopia >1.0 D, astigmatism ≥1.25 D and anisometropia >1.0 D.

RESULTS

Using receiver operating characteristic (ROC) curves, we could compare the efficiency of VA, VA+2, VAnear, VA in combination with VA+2 and VA in combination with VAnear. Area under the curve (AUC) for VA, VA combined with VA+2 and VA combined with VAnear was 0.841, 0.857 and 0.857, respectively, that is all classified as 'very good' screening tools, whereas VA+2 and VAnear as single screening tools were classified as 'good' with AUC of 0.704 and 0.775, respectively. Using the optimal cut-off limit from the ROC curves, VA above 0.05 LogMAR as cut-off limit showed a sensitivity of 85.2% with a specificity of 74.9%. A slightly higher sensitivity could be found when combining screening tests, but with declining specificities.

CONCLUSION

Visual acuity at distance with the use of LogMAR-based charts is the optimal screening tool of choice; only minor improvements can be obtained combining with other tests.

Evaluation of vision screening in five- to eight-year-old children living in Region Västra Götaland, Sweden - a prospective multicentre study

PURPOSE

To evaluate the current vision screening criteria regarding amblyopia and refractive errors, with emphasis on screening limits and retesting, in Region Västra Götaland (VGR), Sweden. Visual acuity (VA) screening is performed by nurses at primary healthcare centres (PHCs) in 4-year-old children and at school in 6- or 7-year-old children. Children with VA <0.65 (>0.19 logMAR) at either eye are referred. If VA is 0.65 in one or both eyes, a retest is performed by nurses at PHCs and schools, the children are then referred if VA is <0.8 (>0.10 logMAR).

METHODS

We included all children aged ≥5 and <8 years referred between October 2014 and June 2015 from PHCs and schools to the four eye clinics in VGR, with VA ≥0.65 in one or both eyes. At the eye clinic, children underwent assessment of VA, refraction in cycloplegia, eye motility, cover test, stereo test and a slit lamp examination.

RESULTS

Among the 259/295 children (139 female) participating, median age was 5.7 years (5.0-7.8 years) at referral. Glasses were prescribed due to subnormal VA with refractive errors in 20% of the children, 22% displayed heterophoria, none had heterotropia and one younger child had amblyopia. Accurate retesting gave fewer false-positive referrals.

CONCLUSION

Our results showed that a vision screening referral cut-off limit of VA <0.65 would leave undetected refractive errors. Residual amblyopia was uncommon. Accurate referral criteria, retesting and training of those performing the screening as well as re-evaluation of the screening programme are all important.

Normative visual acuity in Chinese preschoolers aged 36 to <48 months as measured with the linear HOTV chart: the Yuhuatai Pediatric Eye Disease Study

OBJECTIVES

To document population-based normative data for uncorrected visual acuity (UCVA) in Chinese preschoolers aged 36 to <48 months without any sight-affecting abnormalities and to evaluate its effectiveness for vision referral.

METHODS

In a population-based cohort of children in the Yuhuatai Pediatric Eye Disease Study, UCVA was measured by using the linear HOTV chart, followed by other ocular examinations. Reference population was defined as children without ophthalmic abnormalities or refractive error. Normative UCVA was obtained from the reference population. The UCVA referral cut-off was defined as the lowest fifth percentile of the normative distribution of UCVA.

RESULTS

The analysis cohort consisted of 1606 Chinese preschoolers aged 36 to <48 months. Among them, a total of 791 children were included in the reference population. The 5th, 50th and 95th percentiles of the UCVA distribution in the reference population were 20/40, 20/32 and 20/25, respectively. UCVA improved with increasing age (p<0.0001), but worsen if prematurity was presented (p=0.041). Using the fifth percentile, UCVA cut-off from the reference population generated referral rates of 26.9% in the general population, and detected more than 86% of amblyopia cases.

CONCLUSIONS

We propose that UCVA no better than 20/40 measured by linear HOTV chart should be a referral cut-off for Chinese preschoolers aged 36 to <48 months. Most amblyopia cases can be identified with this age-specific and chart-specific UCVA cut-off.

Zagreb Amblyopia Preschool Screening Study: near and distance visual acuity testing increase the diagnostic accuracy of screening for amblyopia

AIM

To present and evaluate a new screening protocol for amblyopia in preschool children.

METHODS

Zagreb Amblyopia Preschool Screening (ZAPS) study protocol performed screening for amblyopia by near and distance visual acuity (VA) testing of 15 648 children aged 48-54 months attending kindergartens in the City of Zagreb County between September 2011 and June 2014 using Lea Symbols in lines test. If VA in either eye was >0.1 logMAR, the child was re-tested, if failed at re-test, the child was referred to comprehensive eye examination at the Eye Clinic.

RESULTS

78.04% of children passed the screening test. Estimated prevalence of amblyopia was 8.08%. Testability, sensitivity, and specificity of the ZAPS study protocol were 99.19%, 100.00%, and 96.68% respectively.

CONCLUSION

The ZAPS study used the most discriminative VA test with optotypes in line as they do not underestimate amblyopia. The estimated prevalence of amblyopia was considerably higher than reported elsewhere. To the best of our knowledge, the ZAPS study protocol reached the highest sensitivity and specificity when evaluating diagnostic accuracy of VA tests for screening. The pass level defined at ≤0.1 logMAR for 4-year-old children, using Lea Symbols in lines missed no amblyopia cases, advocating that both near and distance VA testing should be performed when screening for amblyopia.

Determinants and outcome of unsuccessful referral after positive screening in a large birth-cohort study of population-based vision screening

PURPOSE

The efficacy of population-based vision screening is hampered by unsuccessful referral after a positive screening test. We studied the nature and causes of unsuccessful referral in a 7-year birth cohort study of vision screening in Rotterdam, the Netherlands.

METHODS

All parents of children who had been unsuccessfully referred were asked whether they recalled the referral. Reasons for noncompliance, if any, were identified using semi-structured interviews. Screening records were checked for written evidence of the referral. The parents' fluency in Dutch and their socioeconomic status were also assessed.

RESULTS

Of the 561 screen-positive children, 129 (23%) had not been referred successfully. For the current study, 97 parents were successfully contacted. Of these, 14 parents had been willingly noncompliant and 83 said they were unaware of the referral, with 47% having poor to moderate fluency in Dutch. In 53 cases, the screening charts contained no written evidence of any referral. Amblyopia was identified in 3 of the unsuccessful referrals.

CONCLUSIONS

In this population-based screening program, 1 of 4 positively screened children was not successfully referred. Apart from parental noncompliance, the unsuccessful referrals can be explained by miscommunication, deficient documentation, and physician noncompliance with screening guidelines. An effective monitoring feedback system may improve the efficacy of child vision screening.

A review of the evidence on the effectiveness of children's vision screening

Screening programmes enable health conditions to be identified so that effective interventions can be offered. The aim of this review was to determine: (1) the effectiveness of children's vision screening programmes; (2) at what age children should attend vision screening; and (3) what form vision screening programmes should take to be most effective. A literature review on the effectiveness of vision screening programmes in children aged 0-16 years was undertaken. Eligible studies/reviews were identified through clinical databases, hand searches and consultation with expert reviewers. The methodological quality of papers was rated using National Health and Medical Research Council (NHMRC) guidelines. Screening of children 18 months to 5 years, and subsequent early treatment, led to improved visual outcomes. The benefit was primarily through treatment of amblyopia, with improved visual acuity of the amblyopic eye. However, the overall quality of the evidence was low. The implication of improved visual acuity (e.g. any potential impact on quality of life) was not considered. Without consideration of 'quality of life' values, such as loss of vision in one eye or possibility of future bilateral vision loss, the cost-effectiveness of screening is questionable. Screening and treating children with uncorrected refractive error can improve educational outcomes. Evidence suggested that screening occur in the preschool years. Orthoptists were favoured as screening personnel; however, nurses could achieve high sensitivity and specificity with appropriate training. Further research is required to assess the effectiveness of neonatal screening. Most studies suggested that children's vision screening was beneficial, although programme components varied widely (e.g. tests used, screening personnel and age at testing). Research is required to clearly define any improvements to quality of life and any related economic benefits resulting from childhood vision screening. The evidence could be used to guide optimization of existing programmes.

Vision screening for amblyopia in childhood

BACKGROUND

Amblyopia is a reversible deficit of vision that has to be treated within the sensitive period for visual development. Screening programmes have been set up to detect this largely asymptomatic condition and refer children for treatment while an improvement in vision is still possible. The value of such programmes and the optimum protocol for administering them remain controversial.

OBJECTIVES

The objective of this review was to evaluate the effectiveness of vision screening in reducing the prevalence of amblyopia.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2008), MEDLINE (January 1950 to August 2008) and EMBASE (January 1947 to August 2008). The electronic databases were last searched on 15 August 2008. No language restrictions were placed on these searches. No handsearching was done.

SELECTION CRITERIA

We planned to analyse data from randomised controlled trials and cluster-randomised trials comparing the prevalence of amblyopia in screened versus unscreened populations.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study abstracts identified by the electronic searches. Full text copies of appropriate studies were obtained and, where necessary, authors were contacted. No data were available for analysis and no meta-analysis was performed.

MAIN RESULTS

Despite the large amount of literature available regarding vision screening no trials designed to compare the prevalence of amblyopia in screened versus unscreened populations were found.

AUTHORS' CONCLUSIONS

The lack of data from randomised controlled trials makes it difficult to analyse the impact of existing screening programmes on the prevalence of amblyopia. The absence of such evidence cannot be taken to mean that vision screening is not beneficial; simply that this intervention has not yet been tested in robust trials. To facilitate such trials normative data on age-appropriate vision tests need to be available and a consensus reached regarding the definition of amblyopia. In addition, the consequences of living with untreated amblyopia have yet to be quantified and a cost-benefit analysis carried out.

Screening for amblyopia in childhood

BACKGROUND

Amblyopia is a reversible deficit of vision that has to be treated within the sensitive period for visual development. Screening programmes have been set up to detect this largely asymptomatic condition and refer children for treatment while an improvement in vision is still possible. The value of such programmes and the optimum protocol for administering them remain controversial.

OBJECTIVES

The objective of this review was to evaluate the effectiveness of vision screening in reducing the prevalence of amblyopia.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Group Trials Register, on The Cochrane Library Issue 2, 2005, MEDLINE (1966 to May 2005 week 1) and EMBASE (1980 to 2005 week 19). No language restrictions were placed on these searches. No handsearching was done.

SELECTION CRITERIA

We planned to analyse data from randomised controlled trials and cluster-randomised trials comparing the prevalence of amblyopia in screened versus unscreened populations.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study abstracts identified by the electronic searches. Full text copies of appropriate studies were obtained and, where necessary, authors were contacted. No data were available for analysis and no meta-analysis was performed.

MAIN RESULTS

Despite the large amount of literature available regarding vision screening no trials designed to compare the prevalence of amblyopia in screened versus unscreened populations were found. Data currently under preparation may be available for updates to the review.

AUTHORS' CONCLUSIONS

The lack of data from randomised controlled trials makes it difficult to analyse the impact of existing screening programmes on the prevalence of amblyopia. The absence of such evidence cannot be taken to mean that vision screening is not beneficial; simply that this intervention has not yet been tested in robust trials. To facilitate such trials normative data on age-appropriate vision tests need to be available and a consensus reached regarding the definition of amblyopia. In addition, the consequences of living with untreated amblyopia have yet to be quantified and a cost-benefit analysis carried out.

Non-cycloplegic refractive screening can identify infants whose visual outcome at 4 years is improved by spectacle correction

The Second Cambridge Population Infant Vision Screening Programme using the VPR-1 videorefractor without cycloplegia was undertaken in order to identify those infants with refractive errors who were potentially amblyogenic or strabismogenic. Infants identified at eight months were entered into a control trial of treatment with partial spectacle correction and underwent a long-term follow-up that monitored a wide range of visual, visuoperceptual, visuocognitive, visuomotor, linguistic and social development. In the present paper, the authors report on the outcome measures of visual acuity and strabismus. Poor acuity was defined as a best-corrected acuity of 6/12 or worse on crowded letters or 6/9 or worse on single letters, at age 4 years. Acuity was measured in 79 infants who were significantly hyperopic and/or anisometropic at 11-12 months of age, 23 who showed hyperopia of +3D but less than +3.5D, 196 control subjects, 14 controls with refractive errors, and 126 others who showed an accommodative lag on screening but were not significantly hyperopic on first retinoscopy. There was a poorer acuity outcome in the untreated group of hyperopes compared to controls (p < 0.0001) and to the children who were compliant in spectacle wear (p < 0.001) or who were prescribed spectacles (p < 0.05). Children who were significantly hyperopic at eight months were also more likely to be strabismic by 5.5 years compared to the emmetropic control group (p < 0.001). However, the present study did not find a significant difference in the incidence of strabismus between corrected and uncorrected hyperopic infants. Children who were not refractively corrected for significant hyperopia were four times more likely to have poor acuity at 5.5 years than infants who wore their hyperopic correction, supporting the findings of the First Cambridge Population Infant Vision Screening Programme.

Hyperopia and educational attainment in a primary school cohort

BACKGROUND

Vision screening addresses the visual impairments that impact on child development. Tests of long-sightedness are not found in most school screening programmes. The evidence linking mild-moderate hyperopia and lack of progress in school is insufficient, although strengthened by recent findings of developmental problems in infants.

AIMS

To report on the relation between hyperopia and education test results in a cohort of primary school children.

METHODS

A total of 1298 children, aged 8 years, were screened for hyperopia on the basis of fogging test results. School test results (NFER and SATs) were compared between groups categorised by referral status and refractive error.

RESULTS

A total of 166 (12.8%) fogging test failures were referred for ophthalmic assessment. Ophthalmic tests on 105 children provided an accurate diagnosis of vision defects, for reference to their education scores. Fifty per cent of the children examined by optometrists required an intervention (prescription change, glasses prescribed, or referral). Mean (95% CI) NFER scores of children with refractive errors (summed for both eyes) >+3D (98.4, 93.0-103.8, n = 32) or >+1.25D (best eye) (99.3, 93.0-105.6, n = 26) were lower than the respective scores of children with a less positive refractive state (104.8, 100.7-108.9, n = 43) (103.6, 99.7-107.4, n = 49), the non-referred group, and total sample. The SATs results followed a similar trend. A high proportion of the fogging test failures (16%) and confirmed hyperopes (29%) had been referred to an educational psychologist, and the latter group contributed substantially to the poor education scores.

CONCLUSIONS

The results of this study provide further evidence for a link between hyperopia and impaired literacy standards in children.

Vision screening for children: current trends, technology, and legislative issues

PURPOSE OF REVIEW

The purpose of this review is to examine current trends in vision screening for children.

RECENT FINDINGS

Literature within the past year regarding children's vision screening has been dominated by clinical validation studies of autorefractors or photoscreeners that allow the detection of amblyogenic refractive errors, misalignment of the eyes, or media opacities. New technologies reported include wave-front analysis for amblyogenic factors and a visual evoked potentials-based screening tool for the preverbal child. Studies evaluating the goals of the screening program, the target population, and the physical limitations of the screening environment have prompted multipronged or hybrid studies designed to more accurately detect vision problems, particularly in the preschool child, in whom cooperation and cognitive development affect reliability of results. State and federal legislation in the United States has been proposed or adopted to regulate and partially fund pediatric vision screening and comprehensive examinations.

SUMMARY

Through improvements and new developments in technology, study design, the efforts of organized medicine, and legislative initiatives, vision screening for children continues toward the goal of bringing all children with eye disease or vision problems to treatment in a timely fashion.

The Seoul Metropolitan Preschool Vision Screening Programme: results from South Korea

AIM

To report on a new model of preschool vision screening that was performed in metropolitan Seoul and to investigate the distribution of various ocular disorders in this metropolitan preschool population.

METHODS

Vision screening was conducted on 36 973 kindergarten children aged 3-5 years in a stepwise manner. The first step was home screening using a set of five picture cards and a questionnaire. The children who did not pass the first step (VA <0.5 in at least one eye or any abnormal responses on the questionnaire) were retested with regular vision charts at the regional public healthcare centres. After this retest, some children were referred to ophthalmologists. The referral criteria for visual acuity were <0.5 at 3 years and <0.63 at 4 or 5 years in at least one eye.

RESULTS

Of those screened, 7116 (19.2%) children did not pass the home screening tests and 2058 (28.9%) out of the 7116 were referred. The results of the ophthalmological examination in eye clinics were only available for 894 children (43.4%) of those who were referred. The rest of the children did not visit ophthalmologists because they had been checked at an eye clinic, were currently under treatment, or for personal reasons. Refractive errors were found in 608 (1.6%) children. Astigmatism was associated in 78.2% of ametropes. Amblyopia was discovered in 149 (0.4%) children and refractive error was the major aetiology with a predominant rate (82.5%). Manifest strabismus was detected in 52 children. The positive predictive value of vision screening for any ophthalmological disorder was 0.77, and 0.49 for significant disorders requiring treatment.

CONCLUSIONS

This preschool vision screening model was highly accessible to the children and their parents, easy to administer, and effective to detect a variety of ocular disorders. However, the participation rate of the referred children in the examinations by ophthalmologists was quite low. The performance and efficiency of this screening programme need to be optimised with further revision.

Vision Health Care Providers?? Attitudes and Experiences with Preschool Vision Screening in Ontario

PURPOSE

The validity of preschool vision screening has been questioned in the light of the World Health Organization's criteria for determining the validity of screening programs. However, recommendations toward preschool screening have been made by a number of organizations. Given the contrasting views of screening, the purpose of this study was to examine visual health care provider experiences and attitudes toward preschool screening.

METHOD

Optometrists, public health administrators, pediatric ophthalmologists, and orthoptists were surveyed about opinions of, recommendations for, and experiences with preschool vision screening in Ontario. The survey focused on four areas, including general opinion of preschool screening, screening standards and practices, provider experience with preschool screening, and barriers to preschool screening. In addition, survey responses were broken down by regional access to health care.

RESULTS

Overall, strong support for preschool vision screening and movement toward standardization of screening practice was found among all surveyed groups. Although support for vision screening in low health care access areas was strong, providers estimated that parent compliance to screening was weaker in low access areas. Providers also reported considerable variability in vision screening practices. In addition, although the majority of providers had been involved in a screening program, the majority was no longer involved because of lack of program organization, structure, and funding. Lack of sufficient funding, public education, organization of screening, training, and government support were listed as barriers to preschool vision screening.

CONCLUSION

Providers are interested in the development of structured screening programs. However, although screening may be a way to offer some level of vision care service to low health care access areas, a number of factors need to be addressed in discussions of vision screening program standards or screening best practice. In general, preschool screening programs need to be structured, be supported, have quality control, and be evaluated.