Vision screening in infants and children: Findings indicative of amblyopia

VA: visual acuity.
* Testing of the fixation reflex involves moving a visual target to and fro in the child's visual space. Each eye is tested separately by occluding the nontested eye. Accuracy is improved if the test is repeated several times. Refer to the UpToDate topic on evaluation of amblyopia in children for further details.
¶ The occlusion objection test involves monitoring the child's response to alternate occlusion of the eyes. Children with equal vision should respond equally, or not at all, to alternate occlusion. Children with moderate-to-severe visual impairment in 1 eye typically become irritable when the eye with better vision is occluded. Refer to the UpToDate topic on evaluation of amblyopia in children for further details.
Δ The vertical prism test is performed using a 10- to 14-diopter vertical prism held (with the base down) in front of 1 eye and then the other. Amblyopia should be suspected if the child is unable to maintain fixation or demonstrates preference for the displaced image (ie, the eye moves upward). Refer to the UpToDate topic on evaluation of amblyopia in children for further details.