Purpose.
Detection of
amblyopia in infants and toddlers is difficult because the current clinical standard for this age group, fixation preference, is inaccurate. Although
grating acuity represents an alternative, studies of preschoolers and schoolchildren report that it is not equivalent to the gold standard optotype acuity. Here, we examine whether the Teller Acuity Cards (TAC) can detect
amblyopia effectively by testing children old enough (7.8 ± 3.6 years) to complete optotype acuity testing.
Methods.
Grating acuity was assessed monocularly in 45 patients with unilateral
amblyopia, 44 patients at risk for
amblyopia, and 37 children with no known
vision disorders. Each child’s
grating acuity was classified as normal/abnormal based on age-appropriate norms. These classifications were compared with formal
amblyopia diagnoses.
Results.
Grating acuity was finer than optotype acuity among amblyopic eyes (medians: 0.28 vs. 0.40 logMAR, respectively, p < 0.0001) but not among fellow eyes (medians: 0.03 vs. 0.10 logMAR, respectively, p = 0.36). The optotype acuity-
grating acuity discrepancy among amblyopic eyes was larger for cases of severe
amblyopia than for moderate
amblyopia (means: 0.64 vs. 0.18 logMAR, respectively, p = 0.0001). Nevertheless, most cases of
amblyopia were detected successfully by the TAC, yielding a sensitivity of 80%. Furthermore,
grating acuity was relatively sensitive to all
amblyopia subtypes (69 to 89%) and levels of severity (79 to 83%).
Conclusions.
Although
grating acuity is finer than optotype acuity in amblyopic eyes, most children with
amblyopia were identified correctly suggesting that
grating acuity is an effective clinical alternative for detecting
amblyopia.
