Page 17 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

Early detection of visual disorders tests
(in Dutch: Vroegtijdige Opsporing Visuele stoornissen (VOV))
Corneal light reflex test
The corneal light reflex test is performed to assess ocular alignment. The test is performed by shining a light into the child eyes from a distance (40cm),with the child fixation on the light, and observing the reflections on the cornea with respect to the pupil. The location of the light reflexes should be symmetric. The test is easy to perform and can, if the test is symmetrical, proof pseudostrabismus.
Cover-uncover and alternating cover test
The monocular cover-uncover test is used to detect manifest strabismus and to distinguish latent from manifest strabismus (heterophoria versus heterotropia). Monocular cover-uncover testing is performed by having the child fixate on a small near object and occluding one eye of the child. The examiner looks for any movement in the non-covered eye. If a movement is present this indicates a manifest strabismus (heterotropia). When there is no movement of the non-covered eye the cover is removed after a short moment. If the covered eye makes a movement in one direct by application of the occlude and in the opposite direction after removal of the occlude this indicates a latent strabismus (heterophoria).
The alternating cover test is also used to detect strabismus. With the child fixating on an object the examiner moves the occlusion from one eye to the other eye, observing the direction of movement of the eye that is uncovered. This test disrupts binocular fusion and does not make a distinction between latent and manifest strabismus. Testing can be done at both near and distance fixation. Foveal fixation, patient attention and cooperation are needed to perform cover testing.
Monocular pursuit
Monocular pursuit is performed by occluding one eye and making a small movement with a pen light or fixation object. When the occlusion of one eye gives a defensive reaction this can be an indication of poor vision in the other, not occluded, eye. Smooth pursuit is in indication of normal vision. The test is used as indirect measurement of VA in young children.
Motility
Eye motility (binocular following) is tested by observing whether a child follows an object smoothly with both eyes simultaneously in 8 directions of gaze. Smooth pursuit
General introduction
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