Disinvestment study of population-wide eye screening in the Netherlands: effect of omission of preverbal eye screening at age 6-9 months

Abstract

Purpose: Around 1980 preverbal screening was added to preschool screening at the Child Health Centers (CHC’s) that screen 97% of all Dutch children. Dutch children are eye-screened 7 times in the age range 0-5 years. The RAMSES birth-cohort study showed that preverbal eye screening contributed little to the detection of refractive amblyopia and that half of strabismic amblyopia cases were discovered outside of screening. Effect of abolishment of eye screening at age of 6-9 months was investigated.

Methods: In a large rural area and a suburb of Amsterdam preverbal screening (cover test, Hirschberg test, eye movements, cornea and pupillary reflexes) was abolished in one of 2 birth cohorts. All children were screened at 1-2 and 3-4 months, but at 6-9 months only the control group (born July-December 2011) was screened. Children in the intervention group (born January-June 2012) did attend consultations at the CHC’s for all other basic screening and vaccinations. Eye screening, in the intervention group, was only performed based on inspection or information from parents. Data was collected from screening records, anonymous questionnaires and on-site observations.

Results: 57 out of 6188 children (0.9%) in the screened group were referred to an orthoptist or ophthalmologist. In the unscreened group 48 out of 5623 children (0.9%) were referred to an orthoptist or ophthalmologist. 11 children in the screened group and 6 in the unscreened group were referred based on the screening tests. All other cases were referred based on strabismus observed by parents or screening physician or because of other visual apparent problems. Amblyopia was diagnosed in 7 (screened group) versus 6 children (unscreened group). Only 1 of these children, in either group, was referred based on the screening test. All cases of diagnosed amblyopia were strabismic or combined-mechanism amblyopia.

Conclusions: Equal numbers of children were referred and found to have amblyopia in the screened and unscreened group. Conspicuous strabismus was noted by parents or screening physicians, while no cases of refractive amblyopia were detected in either group. Weaknesses were that screening physicians were familiar with eye screening in both groups and that in a third of unscreened children the evidence that the child indeed had not been screened was not fully conclusive.

Keywords: 709 screening for ambylopia and strabismus • 417 amblyopia • 723 strabismus: diagnosis and detection