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Updated: Jun 23, 2025
Author Spotlight: An Automated Method for Assessing Visual Acuity in Infants and Toddlers Using an Eye-Tracking System
Published on: March 17, 2023
Unveiling Visual Acuity in 58,712 Four-Year-Olds: Standardized Assessment Defined Normative Visual Acuity Threshold
Mirjana Bjeloš1,2,3, Mladen Bušić1,2,3, Benedict Rak1
1University Eye Department, Reference Center of the Ministry of Health of the Republic of Croatia for Pediatric Ophthalmology and Strabismus, Reference Center of the Ministry of Health of the Republic of Croatia for Inherited Retinal Dystrophies, University Hospital "Sveti Duh", 10000 Zagreb, Croatia.
Insights
This study established new visual acuity (VA) standards for four-year-olds using LEA Symbols®, finding a normative VA cut-off of 0.78 logMAR. These findings suggest updated protocols for preschool vision screening are now recommended.
Area of Science:
- Ophthalmology
- Pediatric Optometry
Background:
- Accurate visual acuity (VA) assessment in young children is crucial for early detection of vision impairments.
- Existing protocols for preschool vision screening may not reflect current standards or the capabilities of modern testing methods.
Purpose of the Study:
- To define the threshold of normal visual acuity (VA), mean monocular and binocular VA, and interocular difference in healthy four-year-old children.
- To establish updated normative data for VA testing in this age group.
- To evaluate the necessity of historical VA testing protocols for preschool children aged four years and older.
Main Methods:
- Analysis of a large cohort (58,712 children) from the Croatian National Registry of Early Amblyopia Detection.
- Visual acuity testing using LEA Symbols® inline optotypes at near and distance, both binocularly and monocularly.
- Application of Receiver Operating Characteristic (ROC) curve analysis to determine a uniform cut-off value for normative VA.
Main Results:
- A total of 16.22% of children were referred for examination, with 92% referred for binocular and 8% for monocular causes.
- Children referred for binocular issues had a VA of 0.3 ± 0.24 logMAR, while those referred for monocular issues had a VA of 0.6 ± 0.21 logMAR.
- The ROC analysis identified a uniform cut-off value for normative VA at 0.78 logMAR.
Conclusions:
- The study provides the largest uniform cohort data for binocular and monocular VA in four-year-olds using the gold standard logMAR chart.
- The established normative data and cut-off value of 0.78 logMAR offer a basis for updated vision screening protocols.
- There is no longer a need to utilize historical protocols for testing VA in preschool children aged four years and older.
Abstract:
The purpose was to define the threshold of normal visual acuity (VA), mean monocular and binocular VA, and interocular difference in the uniform cohort of healthy four-year-old children. All the children were recruited from the Croatian National Registry of Early Amblyopia Detection database. LEA Symbols® inline optotypes were used for VA testing at near and distance, binocularly and monocularly. The pass cut-off level was set to ≤0.1 logMAR. The final sample consisted of 58,712 four-year-old children. In total, 83.78% of the children had unremarkable results, and 16.22% of the children were referred to examination. Of those, 92% of the children were referred due to binocular, and 8% of the children due to monocular causes. The children referred due to binocular causes demonstrated a VA of 0.3 ± 0.24, while the children referred due to monocular causes 0.6 ± 0.21. The ROC curve analysis defined the uniform cut-off value for a normative VA of 0.78. We analyzed the largest uniform cohort of 58,712 children, and have determined normative data for binocular and monocular VA tested with gold standard logMAR chart in four-year-old children. The results presented here established no reasoning to further utilize historical protocols in testing VA in preschool children aged ≥ 4 years.
