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Assessment of visual acuity in children aged 1 1/2-6 years, with normal and subnormal vision
A Rydberg1, B Ericson, G Lennerstrand
1Department of Ophthalmology, Karolinska Institute, Huddinge University Hospital, Sweden.
Insights
Reliable visual acuity testing in young children requires recognition-based tests. Detection and resolution acuity measures, like Stycar Rolling Balls and Teller Acuity Cards, can overestimate true visual function.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Vision Science
Background:
- Assessing visual acuity in young children (1.5-6 years) is crucial for diagnosing and managing visual impairments.
- Existing visual acuity tests vary in methodology, leading to potential discrepancies in measurement.
- Understanding the nuances of different acuity types (detection, resolution, recognition) is key for accurate assessment.
Purpose of the Study:
- To compare the effectiveness of various visual acuity tests in children aged 1.5 to 6 years.
- To evaluate detection, resolution, and recognition acuity measures in children with normal vision, ocular disease, or strabismus.
- To determine which visual acuity tests provide the most reliable measurements in this age group.
Main Methods:
- The study involved 105 children aged 1.5-6 years with varying visual statuses.
- Visual acuity was assessed using detection (Stycar Rolling Balls), resolution (Teller Acuity Cards), and recognition tests (BUD-D, Sheridan Gardiner, LH, HVOT).
- A 'crowding ratio' was calculated to analyze the impact of optotype spacing on acuity measurements.
Main Results:
- Detection and resolution acuity tests (Stycar Rolling Balls, Teller Acuity Cards) tended to overestimate visual acuity.
- Recognition acuity tests, particularly those using linear optotypes (LH, HVOT), showed good agreement and provided more reliable estimates.
- The crowding ratio varied significantly, being highest in children with strabismic amblyopia, indicating reduced visual function in cluttered visual fields.
Conclusions:
- Reliable visual acuity measurement in young children is best achieved using recognition-based tests employing linear optotypes or symbols.
- Detection and resolution acuity assessments may not accurately reflect true visual capabilities in this age group.
- The findings underscore the importance of selecting appropriate visual acuity tests for accurate diagnosis and effective management of pediatric vision disorders.
Abstract:
The aim of the study was to assess different visual acuity tests in the age group 1 1/2-6 years in 105 children with assumed normal vision, visual impairment due to ocular disease or strabismus. Acuity tasks for young children can be divided into three subtypes according to the kind of stimulus used. For "detection acuity", the stimulus should be detected or distinguished from the background, as assessed with the Stycar Rolling Balls. For "resolution acuity", the stimulus pattern should be resolved, as assessed with the Preferential Looking procedure (Teller Acuity Cards). For "recognition acuity", the stimulus must be recognized by the subject as assessed with the BUST-D symbol test, Sheridan Gardiner (S-G) single letters, LH single symbols and line tests, and also the HVOT test. Different acuity values were obtained with regard to detection, resolution and recognition acuities. Assessment with the Stycar Rolling Balls only gave a rough estimate of the visual function. There was an overestimation of the acuity values in all groups of children when using the Preferential Looking technique. Good agreement was found between the LH line and HVOT tests. The BUST-D test, S-G single letters, and LH single symbols gave slightly better acuity values than linear recognition tests. A "crowding ratio" was calculated by dividing the single optotype acuity by the linear acuity, and also by dividing the grating acuity by the optotype linear and single acuity. The crowding ratio varied in the individual children and in the different groups, being highest for strabismic amblyopia. The general conclusion is that reliable visual acuity measurements were not obtained until the visual acuity could be assessed with a recognition test using linear letters or symbols.
