of the 12 772 children tested , 78 % had an unaided distant visual acuity of 6/6 or better in both eyes ( optimal vision ) , 10 % had a distant visual acuity of 6/9 in the worse or both eyes ( near-optimal vision ) and 12 % had a visual acuity of 6/12 or worse in one or both eyes eyes ( definite visual defect ) .
C0042789
vision
C0015392
eyes