Our study findings, particularly the prevalence of refractive error, cannot be directly compared to the results in another recent population-based study that explored refractive error in young children, the MEPEDS (Tarczy-Hornoch K, et al.
IOVS 2008;49:ARVO E-Abstract 3130). In that study, myopia (at least −1.00 D) was found in 6.6% of African-American children (
n = 2993) and in 3.7% of Hispanic children (
n = 3024), with no significant difference between the sexes for each ethnic group. The BPEDS (Baltimore Pediatric Eye Disease Study; Katz J, et al.
IOVS 2008;49:ARVO E-Abstract 1549) found a similar prevalence of myopia (at least −1.00 D) in African-American children (5.5%) and reported a prevalence of only 0.7% in Caucasian children. Although large components of our study methodology are similar to those of the MEPEDS and BPEDS, there are minor but important differences in our approaches to measuring refractive error. With the knowledge gained from our pilot study, which showed that the Retinomax autorefractor (Nikon) overestimated the myopic component of refraction in young children,
16 we decided on the table-mounted autorefractor as the primary method of measuring refractive error in the children aged 24 months or older, as this instrument has been shown to be more reliable.
17 The Retinomax was used in both the MEPEDS and BPEDS in their main refractive test, and retinoscopy was performed only if that test failed or if cycloplegia was refused. In our study, refractive measurements obtained from the Retinomax represented less than 20% of cases. Nonetheless, we found that the prevalence of myopia (at least −0.75 D) in our study (ages 5–6 years) was similar (4.7%) to that reported in the Refractive Error Study in Children (RESC) study (5.7% with stand-alone autorefraction) in 5-year-old children residing in South China.
18 The prevalence of myopia in our study is similar to that in a study of 260 Taiwanese school children (5.8% in 7-year-olds),
12 but much higher than that reported in 1742 Australian school students (<2% in children with a mean age of 6.7 years).
13 No further comparisons could be made with the results of other studies, as they included children of older ages.