Page 107 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

Effectiveness of routine population-wide orthoptic preschool vision screening tests at age 6-24 months in The Netherlands
INTRODUCTION
The Netherlands has one of the most extensive amblyopia screening systems worldwide.1 Children are screened seven times from birth to five years of age.1 In 1901, the first Child Healthcare (CHC) centre was opened in the Netherlands.2 In 1960, measurement of visual acuity (VA) after three years of age was included. Preverbal orthoptic vision screening tests (‘Vroegtijdige Onderkenning Visuele stoornissen (VOV)’: early detection of visual disorders) were introduced in 1980.3,4 Preventive youth healthcare (YHC) physicians and nurses perform eye screening at CHC centres, as part of the screening for general health disorders and vaccinations, of all children younger than four years of age according to the national protocol (‘Opsporing visuele stoornissen 0-19 jaar’).5 This includes inspection of cornea and pupil, pupillary reflexes, fundus reflex and eye motility at 1-2 and 3-4 months to detect congenital disorders like retinoblastoma and cataract. Preverbal orthoptic tests are performed at 6-24 months: Hirschberg test, cover test and pursuit movements , but no fundus reflex testing (Table 1).3-5 At 36 and 45 months VA is tested, respectively, with the Amsterdam Picture Chart (APK) and the Landolt C. Visual acuity measurements are repeated at school at 54-60 months. An overall participation rate of 97% of at least one visit in the first two years is reached, because eye screening is imbedded in a population-based general health care screening and vaccination programme.6
To evaluate the effectiveness of the amblyopia screening in the Netherlands the RAMSES birth-cohort study (N=4624) was performed. This study showed that preverbal screening contributed little to the detection of refractive amblyopia, while strabismus amblyopia was referred outside of screening in approximately half of cases.7
The Optimisation of Amblyopia Screening study (OVAS) was designed to assess whether and to what extent omission of orthoptic vision screening tests as part of general health screening between the age of 6-24 months would affect the detection of strabismus, refractive and combined-mechanism amblyopia and to confirm whether the omission of routine orthoptic vision screening tests between age 6-24 months would have no negative impact on the severity, time to and total cases of amblyopia detected. Parts of these results concerning screening at age 6-9 months have been published earlier.8 In another previous study the performance of CHC physicians with these orthoptic tests was assessed with semi-structured observations. We now report the outcomes of the total OVAS study, after 5-year follow-up.
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