The use of the ophthalmological services during the preschool age, ocular findings and family background

Childhood vision screening in Canada: public health evidence and practice

OBJECTIVES

Best practice guidelines recommend vision testing in children 3 to 5 years of age for the prevention of amblyopia; however, universal vision screening is controversial. In Canada, amblyopia screening can be the responsibility of physicians, optometrists, and/or Public Health. We review the evidence underlying preschool vision screening for amblyopia using an Evidence-based Public Health (EBPH) approach, and consider implications for the Public Health provision of universal screening programs for amblyopia in Canadian jurisdictions in light of present practices.

METHODS

We searched the literature to address each major screening criterion (disease, test, treatment, program requirements) necessary to support preschool vision screening for amblyopia. We also reappraised papers cited in two systematic reviews related to the impact of vision screening. The Chief Medical Officer of Health of each province/territory was sent a short survey asking whether there currently was a Public Health preschool vision screening program in place and if so, for specifics about the program.

RESULTS

An EBPH approach to the literature with respect to the criteria for screening and available intervention studies support amblyopia screening by Public Health. There is a public health divide in amblyopia screening practice in Canada; while some provinces maintain organized programs, others have chosen to delegate the task to other professionals, without a concurrent surveillance function to monitor disparities in uptake.

CONCLUSIONS

Amblyopia deserves attention from Public Health. Efforts should be made to maintain existing programs, and provinces without organized screening programs should reconsider their role in the prevention of inequities with regard to preventable blindness in Canadian children.

The longitudinal study of the northern Finland birth cohort of 1966

The Northern Finland birth cohort comprises 12,058 live births in 1966-96.3% of all births in the region. The investigation was started during pregnancy and the last follow-up of the total series was at the age of 14 years, when the coverage was still large. Smaller samples of the children and data for the study population from national registers were also examined for the older age groups. The health and development of the children was studied, with special emphasis placed on obtaining reliable incidence figures for neurological handicaps and their correlation with perinatal events. In particular, the correlation between low birthweight and handicapping conditions was documented thoroughly. The indicators predictive of low birthweight among the biological characteristics of the mother and the social conditions of the mother and family, included maternal smoking during pregnancy. The latter was associated not only with adverse perinatal outcome but also with reduction in educational achievement and height among survivors.

Preschool vision screening for amblyopia and strabismus. Programs, methods, guidelines, 1983

Amblyopia and strabismus, which afflict at least 5% of children, require treatment early in life for best visual results. At present, many such children are treated late or not at all. Mass screening at preschool age, and perhaps ultimately of infants, appears the only viable solution to this problem. To ascertain the present status of preschool screening in the United States, on-site visits, mail questionnaires and telephone interviews were used to study existing preschool vision screening programs at the federal, state and private organization levels. We estimate that, at most, 21% of preschool children receive any form of vision screening. Only two states, Michigan and Minnesota, have legislated requirements for such screening. Several organizations have attempted to establish screening guidelines, with suggestions of specific test and referral criteria. These guidelines are reviewed. The guidelines are of particular interest because screening programs following them typically indicate far lower prevalence rates than most studies indicate actually exist, suggesting that the guidelines result in underreferrals. In order to assess this matter, vision screening methods appropriate for preschoolers or infants, based on current evidence, are reviewed. Stereoscopic testing, utilizing a random dot stereogram format, appears the best instrument available for amblyopia and strabismus screening, but large scale comparative studies of the different test methods are needed to arrive at a final determination. Suggestions are made for the physician interested in initiating preschool vision screening programs.

Sex differences in refraction errors up to the age of 15

A health inquiry concerning vision and corrective lenses at the age of 14 was carried out in a northern Finland series about 12,000 children followed up since birth. Data were obtained from more than 99% of cases. 34% of the girls and 18% of the boys had corrective lenses. 55% of the study population were living in the province of Oulu, and the ophthalmological records of these children were analysed (N 1939). The ophthalmological records covered 67% of the children with lenses in the province of Oulu. 71% of the girls with lenses, and 66% of the boys had these for myopia, both myopia and hyperopia were less common among the boys, but the cases were more pronounced. The children with lenses were on average taller and heavier and the myopic children had a better mean ability at school.