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Vision screening in children is aimed primarily at detecting non-strabismic amblyopia (other forms of vision defect are generally evident to parents). Such non-strabismic amblyopia occurs mostly as a result of uncorrected refractive errors.1,2 In the December 2003 report by the Child Health Sub-group3 it was recommended that all 4−5 year olds should receive vision screening. The Health For All Children 4 (HFAC4, 2003) “Hall Report”4 and the Children’s Eye Health Working Party guidelines5 similarly suggest vision screening should be undertaken in all 4–5 year olds. This advice is in accord with the results of the first randomised controlled trial of treatment for amblyopia,2 which found that treatment of moderate amblyopia (acuity 6/36−6/18) in preschool aged children was effective. However, currently the coverage of vision screening is patchy, and numbers of specialist screening personnel may be insufficient to meet demand if the recommendation to screen all 4−5 year olds were to be implemented.6 In districts where vision screening is not carried out, optometrists might act as an important safety net by providing an additional route for referral of non-strabismic amblyopes.
As part of an investigation into the genetics of myopia,7 we investigated the age distribution of individuals attending for a sight test at 19 optometry practices in northern England during the period January 2000–December 2001. For subjects attending more than once, only the most recent visit was recorded. Of the 90 884 attendees, age was known for 90 750. None of the optometry practices operated in a manner that would be expected to discourage the attendance of children. The age distribution of this optometric cohort was compared with data from the census of England and Wales, conducted in 2000.
Figure 1 shows the age distribution of the optometric cohort compared with that of the year 2000 census. Although the optometry practices were not selected according to defined epidemiological sampling criteria, the high similarity in the age distribution of the two datasets after the age of 10 suggests the optometry attendees are generally representative of the UK population. However, there was a clear deficit in visits to optometrists in the preschool age group, which was highly significant (χ2 = 4186.4, df = 1; p<0.0001). Attendance to optometrists appeared to increase linearly until about age 11 when it reached adult levels (fig 1, inset). Our analysis suggests that only ∼7% of children aged 0−5 years visit an optometrist (1.48% of visits in the optometric cohort were for infants aged 0−5 years, and there were 16.6 million sight tests carried out in Great Britain in total,8 in the year 2000, suggesting 246 000 tests on the 3.7 million infants in this age group). Because infants in whom a refractive error has been detected are likely to visit their optometrist each subsequent year, this figure must be an overestimate of the proportion attending for the first time—that is, in a screening context.
The fact that a visit to the optometrist is such an exception to the rule at this age underlines the importance of vision screening programmes, and suggests that every effort should be made to implement a comprehensive system of screening at age 4−5 in order to detect children likely to benefit from early treatment for amblyopia. However, where such programmes are not in place, we suggest that encouraging children to visit an optometrist should help in the early referral of non-strabismic amblyopes.
We are grateful to the staff of Conlons Opticians Ltd for access to anonymised patient record information. This work was supported by grants from the National Eye Research Centre (SCIAD015) and the Sir Jules Thorn Charitable Trust (RSC47).