Abstract
Abstract: :
Purpose: In laboratory settings, Teller Acuity Card measurements of visual acuity in infants and young children are typically conducted using a Teller Stage to reduce distractions. In clinical settings, the Acuity Cards are often used without the stage. The purpose of this study is to determine whether normative data obtained using the stage are appropriate for use with results obtained when a stage is not used. Methods: Subjects were 45 children between 3.5 and 30 months of age. Each subject’s binocular grating acuity was measured once with Teller Acuity Cards presented with the stage and once with Acuity Cards presented without the stage. Order of testing was counterbalanced across subjects. Testers were aware that gratings progressed from lower to higher spatial frequencies, but were masked to the absolute spatial frequency of the grating on each card. Testers were also masked to acuity results until testing of the child was completed. Results: On average, acuity tested with the stage was 0.4 octave better than acuity tested without the stage. The difference was larger for toddlers (mean = 0.6 octave, 17 and 30 months of age) than for infants (mean = 0.2 octave, 3.5 and 11 months of age). Repeated measures ANOVA showed that the effect of presentation method was significant (p<0.001), as was the interaction between age and method of presentation (p<0.01). Conclusions: These results suggest that normative grating acuity data obtained with the Teller Acuity Cards presented with the stage (Salomao & Ventura 1995; Mayer et al 1995) need to be adjusted downward by 0.2 to 0.6 octave, depending on age, to be appropriate for use with when acuity cards are presented without the use of the stage.
Keywords: infant vision • clinical laboratory testing • visual acuity