Page 83 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

Semistructured observation of population-based eye screening in The Netherlands
close to their own formal teaching. Their training contrasted starkly with that of the CHC physicians who follow a one-day course for eye screening once every five years. It is possible that orthoptists with years of experience would have been more lenient in some parts and more strict in other parts of the examination. In addition, the two orthoptic students were not trained observers although they followed standard procedures for semi-structural observations, like testing for concordance by comparison of a week of simultaneous observations and were coached for the semi-structural observations by their tutor at Utrecht University of Applied Sciences.
Secondly, the test performance could be biased, because the CHC physicians and nurses were presumably on their “best behaviour” while being observed, so this study might represent a maximum standard of test performance.
Thirdly, we do not know whether the children who were not referred did not have amblyopia or another eye disorder. Two of the eight referred children were false positives. In that sense we have no gold standard with which to compare the quality of the examinations. Finally, with 100 days of observation the sample size was still limited. The question is then whether the cover test should be used at all for eye screening in the general population when not performed by orthoptists. The study by Williams and colleagues showed that the cover test has a sensitivity of 25% (range 9-41%) before the age of 25 months. 18
The performance of cover test could be improved with extra courses, but this would increase costs. Another possibility would be to abolish this part of the screening.
CONCLUSIONS
In summary, Hirschberg test, fundus red reflex, and VA were adequately tested in most cases. Cover-uncover test, alternating-cover test, and eye motility were often performed inadequately. Pupillary reflexes were skipped often as room lights could not be dimmed.
ACKNOWLEDGEMENTS
We gratefully acknowledge the support of all CHC physicians, nurses and practice assistants at Public Health Service Icare.
This study was supported by the Foundation Lijf en Leven. The study sponsor had no role in the study design, neither in the collection, analysis, and interpretation of the data nor in the writing of the report or in the decision to submit the paper for publication. The authors had no commercial or propriety interest.
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