Page 82 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

CHAPTER 4
DISCUSSION
We found that the Hirschberg test and the fundus red reflex in children aged 1-24 months and VA measurements in children aged 36-45 months were performed in accordance with the guidelines in most cases. All examinations at the Icare CHC Centres were performed by CHC physicians, except the VA measurements, which were performed by CHC nurses and CHC physicians. The orthoptic examinations: cover-uncover test, alternating-cover test and eye motility were often not performed correctly. Either the eye was not covered completely or switching from the covered to the uncovered eye happened too quickly for the child to pick up fixation. In most cases, eye motility was not maximally tested in all eight directions of gaze; some even had made the children make a circular movement around the primary position, which had been taught by an instructor long ago. Pupillary reflexes should be tested in dim illumination, but due to the fact that the room lights could not be dimmed in many cases, pupillary reflexes were often not tested.
Finally, the monocular pursuit was not tested in the majority of children. A smooth monocular pursuit movement at the age of 6-24 months provides an indirect indication of good VA of that eye. Amblyopic patients have poor fixation stability and unsmooth monocular pursuit in their ambyopic eye as compared with visually health people.16 CHC physicians were often unaware of the true purpose of this test.
In another part of the OVAS study, anonymous questionnaires were sent to all participating CHC physicians9. In 56 out of 80 sent questionnaires, CHC physicians reported the orthoptic tests at 6–9 months to be difficult. Seventy-five percent of CHC physicians found the cover test difficult, 50% found monocular pursuit difficult, and 25% considered testing eye motility difficult. Only 35% of these CHC physicians wanted to have more training in eye screening.
König and Barry showed that eye screening had low effectiveness when performed by untrained general practitioners or paediatricians due to limited experience with eye examination.17 In contrast, screening had high effectiveness when carried out by nurses who were professionally trained to do the screening examination. Most orthoptic tests require a lot of experience to do them well, which is difficult to be obtained within a one- day course, repeated once every five years.
A first limitation of this study was that the two orthoptic students used criteria based on their almost concluded four years of study to become an orthoptist. They were still
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