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Monocular acuity norms for the Teller Acuity Cards between ages one month and four years
D L Mayer1, A S Beiser, A F Warner
1Department of Ophthalmology, Children's Hospital, Boston, MA 02115.
Insights
New norms for monocular grating acuity using the acuity card procedure (ACP) and Teller Acuity Cards (TAC) are now available. These updated norms are suitable for clinical applications and improve upon previous guidelines.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Visual Development
Background:
- Accurate measurement of visual acuity in young children is crucial for early detection of visual impairments.
- The acuity card procedure (ACP) with Teller Acuity Cards (TAC) is a common method for assessing visual acuity in infants and toddlers.
- Existing norms may not be optimal for all clinical applications.
Purpose of the Study:
- To establish clinical norms for monocular grating acuity and interocular acuity differences.
- To validate these norms for use with the acuity card procedure (ACP) and Teller Acuity Cards (TAC).
- To provide updated guidelines for assessing visual acuity in children.
Main Methods:
- Monocular acuities were measured in 460 children aged 1 month to 4 years.
- Inclusion criteria ensured a healthy cohort with normal visual development and refraction.
- Testing was conducted by trained ACP testers using TAC, with specific awareness of spatial frequency.
Main Results:
- High completion rates (99%) and efficient testing times (3.2-8.4 minutes) were achieved.
- New monocular acuity norms, including 95% and 99% prediction limits, were derived.
- The new norms showed higher spatial frequencies for younger children compared to preliminary norms, with similar results for older children.
- Interocular acuity differences were minimal (0-0.5 octave) in 99% of subjects.
- Test-retest and inter-tester reliability were high (≥90% within 0.5 octave).
Conclusions:
- The study successfully derived and validated new monocular acuity norms for clinical use.
- These updated norms are appropriate for the acuity card procedure (ACP) and Teller Acuity Cards (TAC).
- The findings recommend replacing preliminary ACP norms with these new, clinically relevant guidelines.
Purpose:
To derive norms for monocular grating acuity and interocular acuity differences that are appropriate for clinical applications using the acuity card procedure (ACP) and Teller Acuity Cards (TAC).
Methods:
Monocular acuities were measured in 460 children in 12 age groups between 1 month and 4 years. Inclusion criteria were term birth, good general health and normal development, normal eyes, and cycloplegic refraction within specific limits. Each child was tested by two ACP testers who were aware of TAC spatial frequency but not grating location during testing.
Results:
Three monocular tests were completed in the first session in 99% of children. Median time to complete the tests of both eyes ranged from 3.2 to 8.4 minutes. Monocular acuity norms were calculated using 95% and 99% prediction limits. The new norms spanned higher spatial frequencies than the preliminary ACP norms between ages 1 month and 18 months but were similar between 24 and 36 months. The lower normal 2.5% limits were similar to lower limits of other normative studies. The interocular acuity difference was zero or 0.5 octave in 99% of subjects of all ages. Acuities obtained by the same tester on different days and by different testers on the same day were within 0.5 octave in at least 90% of subjects, comparable to previous studies.
Conclusions:
This study provides monocular acuity norms that are appropriate for clinical settings in which the ACP and TAC are used and should replace the preliminary ACP norms.