Figure 4
Visual acuity. Normative data from typically developing children (age 0–12 years) are shown in red70 with upper and lower bound of the 95% confidence interval in grey dashed lines (extracted from the separate original studies70). Note that before the age of 30 months, visual acuity could be estimated only with a preferential looking test such as the Teller acuity chart (TAC)71. From the age of 30 months, visual acuity could be assessed with symbols the child named, gestured or matched. Distant (green) and near (blue) visual acuity in our cohort of children with DS as a function of calendar age. Solid lines are Loess lines fitted to the data. Note the gradually improving visual acuity of children with DS and typically developing children. The acuities of the children with DS lie above the norm scores indicating that children with DS scored poorly on visual acuity, near visual acuity being even worse than distant visual acuity (mean difference 0.11 ± 0.32, paired t-test t(73) = -2.900, p = 0.005). Normative distant visual acuities were obtained from: Salomao et al.38, (TAC, n = 646, 0–30 months, red crosses), Pan et al.39 (HVOT, n = 1722, 30–72 months, red circles), Lai et al.40 (Landolt-C, n = 212, 3–6 years, red stars), Huurneman et al.35 (Tumbling E, n = 75, 4–8 years, red x-es), Jeon et al.41 (Tumbling E, n = 78, 5–11 years, red triangles), Dobson et al.42 (ETDRS, n = 252, 5–12 years, red squares). Grey dashed lines: upper and lower bound of the 95% confidence interval of the original norm data.
