The Rotterdam C-chart: norm values for visual acuity and interocular differences in 5-year-old children
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1Department of Physiology I, Erasmus University, Rotterdam, The Netherlands.
Insights
The new Rotterdam C-chart improves visual acuity testing for children. This chart is suitable for developmental studies and assessing visually impaired children.
Area of Science:
- Ophthalmology
- Pediatric Optometry
Background:
- Conventional C-charts present limitations for assessing visual acuity in young children and those with visual impairments.
- Issues include unequal optotype spacing, inconsistent crowding, insufficient large optotypes, and ceiling effects.
Purpose of the Study:
- To introduce the Rotterdam C-chart, designed with 0.1-log steps and consistent crowding.
- To establish normative values for visual acuity in 5-year-old children using this new chart.
Main Methods:
- The Rotterdam C-chart was used to test visual acuity in 201 five-year-old children at 6m and 40cm distances.
- Results were compared with those from 24 young adults.
Main Results:
- Mean visual acuity in 5-year-olds was lower than in adults, but the distribution patterns were similar.
- The Rotterdam C-chart demonstrated comparable crowding across all lines.
Conclusions:
- The Rotterdam C-chart is a suitable tool for developmental studies of visual acuity.
- It is effective for assessing visual acuity in young children and those with visual impairments.
Abstract:
Common C-charts are often not suitable for developmental studies and assessment of visual acuity in young and visual impaired children, because of unequal steps between lines, uncomparable crowding, inadequate number of large optotypes on the first line and ceiling effects. Therefore a new C-chart (the Rotterdam C-chart) was developed on which optotypes on successive lines decreased in 1/3-octave steps (0.1-log steps) and on which crowding was comparable over the entire chart. Norm values for binocular and monocular visual acuity at test distances of 6 m and 40 cm and norm values for interocular acuity differences in 5-year-old children were determined by testing 201 5-year-olds with this chart. Results were compared to those obtained in 24 young adults. Although mean binocular and monocular acuity of the 5-year-olds were significantly lower than in adults, the distribution of acuity assessments were similar in the children and adults. Therefore, the Rotterdam C-chart seems suitable for developmental studies and for the assessment of visual acuity in young and visually impaired children.