Page 99 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

Effect of omission of population-based eye screening at age 6-9 months in the Netherlands
For the unscreened group, 88.9% of preventive CHC physicians estimated their own percentage of screened children for predetermined reasons at 10% or lower. For non- predetermined reasons (mainly accidently or out of routine) 88.6% of preventive CHC physicians estimated their own percentage of screened children in the unscreened group at 10% or lower.
On-site observations
Semi-structured daylong observations were made of physicians screening children aged 0-4 years, including children from the birth cohorts, by two orthoptic students. The results of all the on-site observations, comprising also the 0-6 months and visual acuity testing at age 3 and 4 years, will be published separately. General impression was that visual acuity was measured well.
In the 6-24 months age range, the two orthoptic students observed 157 children, examined by 23 preventive CHC physicians. The Hirschberg test was almost always performed adequately. The cover test was not performed in 35%; the alternating cover test not in 38%. Of the performed cover tests and alternating cover tests, incomplete covering of the eye and/or too quick switching from the covered to the uncovered eye was noted in 37% and 50%, respectively. Only five out of 23 physicians always performed the cover test correctly, according to the orthoptic students. Motility was performed in 68% of observed children, but only in 7% fully and in all gaze directions. Pursuit movements and pupillary reflexes were performed in 36% and 6% respectively.
DISCUSSION
Our study demonstrated that there is little difference in referral rate with or without preverbal eye screening at the age of 6-9 months. Most children were referred because of observed strabismus or visually apparent disorders. These disorders are detected at the CHC visit regardless of specific eye screening. All cases of amblyopia were strabismus or combined-mechanism amblyopia, and none were pure refractive amblyopia, which was to be expected as visual acuity was not measured.
This study intended to compare population-based, general-health infant screening with and without specific eye screening and there was little difference in referral rate with or without preverbal eye screening. A weakness of the comparison was, however, that the physicians may have detected more cases than physicians who were not trained to perform eye examinations would have detected: (i) the physicians were
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