Page 135 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

High rate of failed visual-acuity measurements with the Amsterdam Picture Chart in screening at the age of 36 months
INTRODUCTION
In the Netherlands, child healthcare (CHC) physicians or nurses screen all children on general health disorders at Child Healthcare Centres (CHC’s), where parents are invited to have their child examined. Coverage is between 95% and 100% in the first year, declining thereafter. The eyes of the children are screened seven times, at the ages of 1-2, 3-4, 6-9, 14-24, 36, 45 and 54-60 months. The vision screening programme has been shown to be effective in detecting amblyopia in the Rotterdam Amblyopia Screening Effectiveness prospective birth-cohort Study (RAMSES study).1,2 Eye screening at 0-4 months includes inspection of the anterior segment, Hirschberg test, pupillary reflexes and the fundus red reflex. At 6-24 months eye screening also comprises cover test, alternating cover test, eye motility and monocular pursuit movements. At 36, 45 and 54-60 months, visual acuity (VA) is measured. At 36 months the Amsterdam Picture Chart (APK) is used.3 At 45 and at 54-60 months Landolt-C optotypes are used.3
The APK was developed in the early 1950s in Amsterdam and has eleven different pictures (Figure 1). These eleven pictures were found recently to have different thresholds.4 In contrast with Landolt-C and Snellen’s E-optotypes, the width of the lines of the APK optotype is not one-fifth, but one-tenth of the size of the optotype. The width of the lines of the Lea Symbols is one-seventh of the size of the optotype. The APK has been favoured by many Dutch orthoptists over years, because children can be tested at the age of 3 successfully in most cases, provided the measurement of VA is done by an orthoptist.5 However, many of the APK pictures are archaic and may be unfamiliar to modern or non-European children.
As the quality of the APK as a psychophysical measurement was found to be low in a previous study by Engin et al.,4 we studied the VA measurement at the age of 36 months in a large birth-cohort study, and found high rates of measurements with insufficient VA and of failed measurements.
133
7