Most recent studies classify around two-third of myopia as early onset called juvenile or school myopia, starting between 9 to 11 years of age and development through the early teenage years (Gilmartin B, 2004: Morgen IG et al. 2014). Usually, infantile myopia has been suggested to be represented by a generally stable refraction status (Blach RK, 1985), whereas in school myopia with modern intensive education, can continue to worse for the next twenty years of life (Medelfart A et al. 1992: Kinge B et al. 1999). Recent studies reported that the increase in the prevalence rates of high myopia only starts to arise after (11-13) years (.Wu JF et al 2013: Xiang F et al 2012). This increase appears to be a consequence of environmental factors, which cause another form of myopia Known as acquired high myopia to differentiate it from a high myopia that has primary genetic factors.( Xiang F et al 2012). This finding supported by a recent study demonstrating that high myopia in younger groups has strong association with education more than high myopia in older groups (Jonas JB et al. 2016)Near
The first suspicion that near work contributes to myopia was raised by
Kepler in 1611, confirmed by Tscherning in 1882, and later has been consistently demonstrated
(Curtin,1985: Owens, 1991). Several epidemiological studies,
examined the association between myopia and near work and have shown positive
finding with some studies (Ip JM et al.2008: Jones-Jordan LA et al.2011: French AN et al. 2013:
Gong Y et al. 2014) and others
studies, reported no relationship (Jones-Jordan LA et al. 2012: Lin Z et al. 2014). Near work appears to be associated
with myopia among children in Australia and Caucasia (Mutti DO et al. 2002: Ip JM et al.
2008) but were not
significantly associated with the prevalence of myopia in Singaporean children(Saw SM et al. 2006). The
Sydney Myopia Study (SMS) which had a stratified random sample a group of
children aged 6 and a group aged
12, with three years in between for reexamination, they found that children who spent time in reading more than half an
hour continuously were more likely to have rapid progression of myopia compared
to those who read for less than half an hour continuously. Furthermore, children
who performed near-tasks at distance less than 30 cm were 2.5 times more likely
to have myopia than those who worked at a longer distance. Similarly, children
who enjoy reading for a long time and those who read at a distance > 30 cm
were more likely have a higher degree of myopia (Ip JM, Saw SM et al. 2008). The Singapore
coherent of risk factor of myopia (SCORM) shown that children who read more
than two books per week were around three times more likely to have higher
myopic refraction compared with those who read less than two books per week.(
Saw SM et al. 2002: Saw SM et al.
2006). In contrast, several
studies have reported that correlations between near work and myopia are not
significant and consistent as those between education and myopia(Mutti DO et al.2009).However,
associations with near work are frequently reported, and a recent meta-analysis
has provided evidence that there is a strong association between near work and
myopia(Huang HM et al. 2015).
Public health organization measures are necessary such as that teachers
and parents take attention of the potential for urging students to develop good
near work related behaviors to inhibit the onset and progression of myopia.