Purpose
Around 1980 preverbal screening was added to preschool screening at the Child Health Centers (CHC’s) that screen 97% of all Dutch children. Eye screening is performed 7 times from 1 month to age 5. 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. Quality of screening exams was now assessed by semi-structured observations.
Methods
Fifteen CHC's with 25 employed youth health care physicians were invited. Of the entire physical examination, only the eye exam was observed in a semi-structured fashion. The observation comprised demographics, parents language skill and detailed assessment of screening physicians' performance of fundus reflex, pupillary reflex, Hirschberg test, cover test, eye motility, visual-acuity measurement, room and chart illumination, type of chart and testing distance.
Results
Of 334 eligible children, 1 was excluded because age was unknown. Two physicians who had examined 2 children each were excluded. Hence 329 children screened by 23 physicians or nurses were analysed; 239 were 0-24 months and 90 were 36-50 months of age. Fundus reflex was performed in 89%, pupillary reflex in 29%, cover test in 65%, alternating cover test in 62%, binocular motility in 67% and monocular motility in 37% of children. At age 6-24 months, incomplete covering of the eye and/or too quick switching from the covered to the uncovered eye was noted in 37% of cover and 50% of alternating cover tests. In assessment of binocular motility at 6-24 months, 7% was tested fully in all directions of gaze. In testing visual-acuity with Amsterdam Picture Chart or Landolt C at age 36-50 months, only in 9% of 90 examinations errors were noted: Distance to the chart was incorrect, the last possible line was not reached or the threshold for the last read line was incorrect. Referral to ophthalmologist or orthoptist (N=30) was based in 80% on measurement of visual acuity.
Conclusions
In their current form, some preverbal screening examinations could be improved or abolished. Fundus reflex in preverbal children and visual acuity measurement in preschool children were assessed correctly in almost all cases.
Keywords: 709 screening for ambylopia and strabismus •
417 amblyopia •
723 strabismus: diagnosis and detection