Childhood Vision Screening in Canada: Public Health Evidence and Practice

Abstract

creening is an important public health strategy for disease prevention. It enables the early identification of disease in asymptomatic individuals and allows them to benefit from direct preventive action. 1 Preschool vision screening has been used for the early detection of amblyopia or lazy eye, which is the leading cause of monocular blindness in the 20 to 70 year age group in higher-income countries. 2 Amblyopia is defined as reduced visual acuity (VA) with no obvious structural or pathologic causes that cannot be improved by corrective lenses. 3 The condition develops within the first six years of life, 4 and once established, persists. Many countries have well-established amblyopia screening programs. 5 In Sweden, for example, children beginning at age 4 are assessed for VA by public health nurses in a program that has an uptake of over 99%. 6 Historically, Canadian public health efforts routinely targeted early detection of amblyopia with trained public health nurses, 7 but a 2007 report 8 showed wide variation in amblyopia screening practices among Canadian provinces. The decline of amblyopia screening seems to be attributed to reservations about the level of evidence that exists to justify such programming. 9 Evidence-Based Medicine (EBM), a concept embraced in clinical practice, privileges evidence derived from randomized controlled trials. 10 In the case of amblyopia screening, a Cochrane systematic review of the literature stated that "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" (ref. 11, pg. 1). This review 11 and a second systematic review 5 both concluded that there was insufficient evidence on the impact of vision screening. The lack of evidence from randomized controlled trials about amblyopia screening has been interpreted as lack of evidence in support of screening, with the result that data from cohort studies and natural experiments, which have shown benefits from screening, have been ignored. In addition, little consideration has been given to whether amblyopia fulfills the World Health Organization's principles for screening 12 (Table 1). We suggest that an Evidence-Based Public Health (EBPH) approach might better bridge evidence and practice in the case of amblyopia screening. 10 EBPH offers a decision-making framework based on research evidence as well as the population characteristics and resources available, and directs policy-makers to accept the 'best available' as opposed to the 'best possible' evidence. 10 In this paper, we review the evidence underlying amblyopia screening

Assessment of availability, awareness and perception of stakeholders regarding preschool vision screening in Kumasi, Ghana: An exploratory study

“…Respondents were of the view that preschool vision screening has not been incorporated into the schools' curriculum, and that no written policy exists for Ghanaian preschoolers. Respondents' views were contrary to the government-supported vision screening programmes and policies for children of school-going age in other countries [9,10,12,13]. An important and novel finding in this current study was the observation that children are not screened at the time of preschool enrolment.…”

“…The introduction of a joint policy statement on vision screening by Practice and Medicine [7] has provided basic recommendations for vision screening in children. Preschool vision screening programmes and policies have been implemented in many countries, including the United States [8], Canada [9], United Kingdom [10], Sweden [11], Australia [12], and South Africa [13]. These vision screenings identify the causes of ocular morbidity in children and offer the best treatment/ management practice, as well as ensuring the consistent availability of vision screening to school-aged children.…”

The Status of Childhood Blindness and Functional Low Vision in the Eastern Mediterranean Region in 2012

“…Mid-level eye care personnel can manage refractive error in children and could provide and maintain visual aids at an affordable cost 42. Screening for amblyopia in 3-5-year-old children, vision-screening for all preterm infants regardless of their previous ROP status, as well as vision-screening programs for all school age children for refractive errors, have been found to be cost-effective measures in the literature 434445. At the minimum, we recommend implementation of these programs through the national eye health care programs of Group 1 and 2 countries.…”

“…Mema et al . justified preschool screening program for amblyopia detection and care that is ongoing in different provinces in Canada 43. The EMR countries with school health programs and vision screening programs could adapt a suitable model for early detection of amblyopia and its causes.…”

Vision screening referral criteria: an audit

“…There has been much debate about the efficacy of primary visual screening in many countries across Europe, [2][3][4][5] the USA and Canada, [6][7][8] Australia, 8,9 Asia 10-14 and the Middle East. [15][16][17][18] Many aspects of visual screening in the UK have been examined including: age at testing, 19,20 tests used, [21][22][23] personnel undertaking the screening, [24][25][26] referral criteria, 21,27 and cost-effectiveness.…”