Page 187 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

To examine how many cases of amblyopia are detected by orthoptic test at 6-24 months the Optimisation of Amblyopia Screening study (OVAS) assessed whether the omission of orthoptic vision screening tests between age 6-24 months would impact the frequency, severity and age of detection of amblyopia. In this study two sequential birth cohorts, with and without vision screening, were followed up from six to 45 months of age. At the age of 6-9 months most children were referred to an orthoptist or ophthalmologist because of observed strabismus or visually apparent disorders, most often noticed by the parents. The detection rate of amblyopia was very low and concerned amblyopia caused by strabismus or caused by strabismus combined with refractive disorder, none solely caused by refractive disorder (chapter 5).
The main outcome of this study was that at the age of 6-24 months strabismus amblyopia and visually apparent eye disorders are mainly detected by the parents before the age VA could be measured and are detected regardless of formal vision screening. Omission of routine preverbal eye screening tests between the age of 6-24 months in the Netherlands did not lead to significant differences in amount of children referred, in total number of cases of amblyopia detected or in the severity of the detected amblyopia. Refractive amblyopia and bilateral amblyopia are detected, almost exclusively, with the VA measurements between 36-60 months (chapter 6).
As a secondary outcome of our study we analysed the effectiveness of VA measure- ments at 36 months with the dated Amsterdam picture chart (APK). Measured VA at 36 months with the APK did not reach threshold in 15.5% of the children, and the measurements themselves failed altogether in another 16.6% of the children. Referral or repeat testing of 1/3 of children is not feasible and on that basis VA measurements at 36 months are no longer performed routinely (chapter 7).
Inspired by the success of the disinvestment study of selected parts of the screening we initiated a pan-European comparison of vision screening programmes in all countries in Europe. Aim of this study is to develop the micro-simulation model further. Guided by and alongside the development of this model an implementation study of vision screening was started, with VA measurement at four and five years, in county Cluj, Romania, where no vision screening is performed routinely yet. The most conspicuous finding in this implementation study was that vision screening in rural areas was much more difficult than in urban areas. In urban areas the kindergartens have resident nurses and the children could be easily screened by these nurses, that they know and trust. In rural areas the kindergartens do not have nurses, the number
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