Is community screening for amblyopia possible, or appropriate?

Screening for foot problems in children: is this practice justifiable?

Podiatry screening of children is a common practice, which occurs largely without adequate data to support the need for such activity. Such programs may be either formalised, or more ad hoc in nature, depending upon the use of guidelines or existing models. Although often not used, the well-established criteria for assessing the merits of screening programs can greatly increase the understanding as to whether such practices are actually worthwhile. This review examines the purpose of community health screening in the Australian context, as occurs for tuberculosis, breast, cervical and prostate cancers, and then examines podiatry screening practices for children with reference to the criteria of the World Health Organisation (WHO). Topically, the issue of paediatric foot posture forms the focus of this review, as it presents with great frequency to a range of clinicians. Comparison is made with developmental dysplasia of the hip, in which instance the WHO criteria are well met. Considering that the burden of the condition being screened for must be demonstrable, and that early identification must be found to be beneficial, in order to justify a screening program, there is no sound support for either continuing or establishing podiatry screenings for children.

Effectiveness of screening preschool children for amblyopia: a systematic review

BACKGROUND

Amblyopia and amblyogenic factors like strabismus and refractive errors are the most common vision disorders in children. Although different studies suggest that preschool vision screening is associated with a reduced prevalence rate of amblyopia, the value of these programmes is the subject of a continuing scientific and health policy discussion. Therefore, this systematic review focuses on the question of whether screening for amblyopia in children up to the age of six years leads to better vision outcomes.

METHODS

Ten bibliographic databases were searched for randomised controlled trials, non-randomised controlled trials and cohort studies with no limitations to a specific year of publication and language. The searches were supplemented by handsearching the bibliographies of included studies and reviews to identify articles not captured through our main search strategy.

RESULTS

Five studies met the inclusion criteria. Of these, three studies suggested that screening is associated with an absolute reduction in the prevalence of amblyopia between 0.9% and 1.6% (relative reduction: between 45% and 62%). However, the studies showed weaknesses, limiting the validity and reliability of their findings. The main limitation was that studies with significant results considered only a proportion of the originally recruited children in their analysis. On the other hand, retrospective sample size calculation indicated that the power based on the cohort size was not sufficient to detect small changes between the groups. Outcome parameters such as quality of life or adverse effects of screening have not been adequately investigated in the literature currently available.

CONCLUSION

Population based preschool vision screening programmes cannot be sufficiently assessed by the literature currently available. However, it is most likely that the present systematic review contains the most detailed description of the main limitations in current available literature evaluating these programmes. Therefore, future research work should be guided by the findings of this publication.

Cost-utility analysis of orthoptic screening in kindergarten: a Markov model based on data from Germany

OBJECTIVE

To estimate the long-term cost-effectiveness of a hypothetical screening program for untreated amblyopia in 3-year-old children conducted by orthoptists in all German kindergartens in the year 2000.

METHODS

A cost-utility analysis was performed for which a decision tree was combined with a Markov model. Incremental costs and effects during the children's remaining lifetime were estimated. The model took into account the probability of treatment without screening, age-specific treatment success rates, costs of screening and treatment, as well as effects of unilateral and bilateral visual impairment caused by amblyopia and other eye diseases coming along later in life on quality of life (utility). Model parameter values were obtained from a field study of orthoptic screening in kindergarten, from the literature, and from expert interviews. Costs were estimated from a third-party payer perspective. Uncertainty was assessed by univariate and probabilistic sensitivity analysis (Monte Carlo simulation).

RESULTS

The incremental cost-effectiveness ratio (ICER) of orthoptic screening was 7397 Euro (euro) per quality-adjusted life year (QALY) when costs and effects were discounted at 5%. In univariate sensitivity analysis, the ICER was sensitive to the uncertainty regarding the utility of unilateral visual impairment and to the discount rate for effects; besides uncertainty regarding the prevalence of untreated amblyopia, the odds ratio of success of treatment when started late, and the probability of treatment without screening had a noticeable but much smaller effect. Monte Carlo simulation yielded a 90% uncertainty interval for the ICER of 3452 euro/QALY to 72 637 euro/QALY; the probability of an ICER <25 000 euro/QALY was 84%.

CONCLUSIONS

The ICER of orthoptic screening seems to fall within a range that warrants careful consideration by decision-makers. Much of the uncertainty in results comes from the uncertainty regarding the effect of amblyopia on quality of life. To reduce this uncertainty, the impact of amblyopia on utility should be investigated.

Amblyopia

Amblyopia is a serious medical condition affecting tens of millions of individuals around the world. For the most part it is correctable, assuming that it is promptly recognized and vigorously treated. Amblyopia may result from form deprivation, anisometropia, or strabismus in infants and young children. Basic research in animal models has shown that the major pathologic changes in amblyopia occur in the visual cortex of the brain. The mainstay of treatment remains patching, although penalization has a role to play in the management of moderate degrees of amblyopia. Better methods for early identification of patients with amblyopia are being developed, along with newer novel methods of treatment.

Economic evaluation of different methods of screening for amblyopia in kindergarten

OBJECTIVE

To compare the cost-effectiveness of 5 methods of screening for untreated amblyopia in kindergarten from a third-party-payer perspective: A) uncorrected monocular visual acuity testing with pass threshold > or =0.5 (20/40) and < or =1 line difference between eyes; B) same as A, but pass threshold > or =0.6 (20/32); C) same as A, plus cover tests and examination of eye motility and head posture; D) same as C, but pass threshold > or =0.6 (20/32); and E) refractive screening without cycloplegia using the Nikon Retinomax autorefractor.

METHODS

A decision-analytic model was used with a time horizon until diagnostic examination. According to the model, all 3-year-old children were screened in kindergarten with 1 of the screening methods. Children with positive screening results were referred to an ophthalmologist for diagnostic examination. Children with inconclusive screening results were either referred to an ophthalmologist directly (option 1) or rescreened by the same method after 1 year and referred to an ophthalmologist if rescreening was positive or inconclusive (option 2). Screening test characteristics and costs were estimated on the basis of a field study in which 1180 3-year-old children were examined by orthoptists in 121 German kindergartens.

RESULTS

Compared with methods A option 1 (A-1), B-1, C-1, C-2, E-1, and E-2, there was at least 1 other method that was both less costly and more effective. The average costs per detected case were lowest for method A-2 (878 Euro), followed by methods B-2 (886 Euro), D-2 (908 Euro), and D-1 (965 Euro). When these methods were compared with each other, the additional costs per extra case detected were 1058 Euro (B-2 vs A-2), 1359 Euro (D-2 vs B-2), and 13 448 Euro (D-1 vs D-2).

CONCLUSIONS

Monocular visual acuity screening with rescreening of inconclusive results had a favorable cost-effectiveness. By adding additional test items, few more cases could be detected. Because of a great proportion of false-negative, false-positive, and inconclusive results, refractive screening was less effective with an unfavorable cost-effectiveness.

Learning-Service Community Partnership Model: a pediatric program evaluation

Pediatric clinical learning experiences in which service provision is offered present a challenge to nursing faculty and students. The Learning-Service Community Partnership Model is a framework in which innovative learning and service provision are an integral part of the pediatric nursing clinical experience. This article discusses a program evaluation of a pediatric community-based health promotion program based on this model. The result from this program evaluation shows that a service program can be effectively managed and provided by pediatric nursing faculty and students. This article describes the shift in moving pediatric learning experiences into the community and validates its importance.

Screening for fetal alcohol syndrome: is it feasible and necessary?

The potential to utilize screening strategies to improve the identification and outcome of persons with fetal alcohol syndrome (FAS) is reviewed. FAS is a condition where screening and surveillance activities would be appropriate. Development of FAS screening and surveillance programs is encouraged because the disorder is expensive. People with FAS have poor outcomes as adults with less than 10% living independently. Several useful tools and models are available. Screening would improve ascertainment and prevalence estimates. Early identification could improve access to services and long term outcome, secondary disabilities and, by extension, excess disability in affected children could be decreased. Lastly, mothers who are at the highest risk to have additional children with FAS could be identified and offered treatment. While both screening and surveillance activities are discussed, the principle focus of this article is a review of the screening process. Two screening tools and several screening methodologies for FAS are available. Since no test will be appropriate in all settings, screening tests need to be selected depending on the setting and population of interest. Screening for FAS should be conducted in a variety of settings and in populations of both high and moderate risk. The results would also provide important data to influence public policy development and resource allocation. Appropriate evaluation of the efficacy, efficiency and effectiveness of FAS screening tools and methodologies would be important before utilization in screening programs.

Preschool vision screening: rationale, methodology and outcome

Although population outcome studies support the utility of preschool screening for reducing the prevalence of amblyopia, fundamental questions remain about how best to do such screening. Infant photoscreening to detect refractive risk factors prior to onset of esotropia and amblyopia seems promising, but our current understanding of the natural history of these conditions is limited, thus limiting the prophylactic potential of early screening. Screening for strabismic, refractive and ocular disease conditions directly associated with amblyopia is more clearly proven, but the diversity of equipment, methods and subject populations studied make it difficult to draw precise summary conclusions at this point about the efficacy of photoscreening. Sensory-based testing of preschool-age children exhibits a similar combination of promise and limitations. The visual acuity tests most widely used for this purpose are prone to problems of testability and false negatives. Moreover, the utility of random-dot stereograms has been confused by misapplication, and new small-target binocularity tests, while attractive, are as yet inadequately field-proven. The evaluation standard for any screening modality is treatment outcome. However, variables in amblyopia classification and quantitative definition differences, timing of presentation, nonequivalent treatment comparisons, and compliance variability have been uncontrolled in virtually all extant studies of amblyopia treatment outcome, making it difficult or impossible to evaluate either the relative efficacy of different treatment regimens for amblyopia or the effects of age on treatment outcome within the preschool age range. The latter issue is a central one, since existence of such an age effect is the primary rationale for screening at younger rather than older preschool ages. The relatively low prevalence of amblyopia makes it difficult to achieve a high screening yield in terms of predictive value, but functionally increasing prevalence by selective screening of high risk populations causes further problems. Unless a "supertest" can be devised, with very high sensitivity and specificity, health policy decisions will be required to determine which of these two characteristics should be emphasized in screening programs. Performance of screening tests can be optimized, however, with adequate training, perhaps via instructional videotapes.