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. Author manuscript; available in PMC: 2016 Apr 27.
Published in final edited form as: Ophthalmology. 2013 Apr 3;120(6):1220–1226. doi: 10.1016/j.ophtha.2012.12.029

Figure 1.

Figure 1

Visual acuity testing protocol.

VA: visual acuity. IOD: inter-ocular difference in visual acuity. *Factoring in results of quality control retest, performed in a subset of children >=36 months under same conditions as presenting VA test (with child’s own glasses if worn): for the first exam of the day for each examiner, and for children with VA worse than 20/32 in either eye, if a second examiner was available. † IOD is defined as inter-ocular VA difference >=2 lines with 20/32 or worse in the worse eye. Decreased VA is defined as worse than 20/50 at any age, or worse than 20/40 if >=48 months of age. ‡ See Methods for definitions of amblyopia risk factors.