Abstract
Background/aims
Amblyopia is the most common visual deficit in children and accurate visual acuity (VA) assessment is essential for diagnosis. While ETDRS high-contrast logMAR VA is the reference standard test for adults, less agreement exists for pre-literate children. A new picture optotype acuity test (The Auckland Optotypes [TAO]) has shown favourable comparison to letter acuity charts but has not yet been evaluated in children with amblyopia. This study aimed to compare VA obtained using TAO to crowded logMAR letters in children age 5–8 years with amblyopia.
Methods
Children with amblyopia (n = 54 [20.37% strabismic, 18.52% anisometropic, 61.11% mixed], mean age 78.30 ± 11.72 months) were recruited from paediatric ophthalmology/orthoptic clinics at Moorfields Eye Hospital NHS Foundation Trust, London, and Cambridge Community Services NHS Trust, Bedford. Best-corrected VA was measured in both the amblyopic eye (AE) and fellow eye (FE) using TAO and a crowded letter acuity chart. Bland–Altman analysis was used to measure 95% limits of agreement (LoA) for VA measures captured (AE, FE and interocular difference [IOD]).
Results
Good agreement between TAO and letter VA measurement was observed (mean bias: AE –0.01, FE 0.01, IOD –0.02). For AE measures 95% LoA were from –0.25 to 0.24 logMAR, this being similar for FE (–0.24 to 0.25) and IOD measures (–0.30 to 0.27).
Conclusion
TAO and letters elicited similar VA in children with amblyopia. TAO could be a useful picture-based chart for paediatric vision assessment.
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Acknowledgements
The authors would like to thank Professor Steven Dakin for his assistance in illustration of TAO optotypes for this paper. We also express our gratitude to the patients of Moorfields Eye Hospital Paediatric Clinic and Cambridge Community Services (Bedford) Eye Clinic and their parents/guardians who kindly gave their time to participate in this research.
Funding
Supported in part by an in-practice research grant from the College of Optometrists (EMMcV), a research award grant from the British Isles Paediatric Ophthalmology and Strabismus Association (BIPOSA) (SML) and by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology (AD-N, PJM, NS). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.
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EMMcV was responsible for the College of Optometrists funding application, assisting with ethics application, recruitment of participants, acquisition of data, statistical analysis and drafting the final manuscript. SML was responsible for the initial study design and concept, protocol development, BIPOSA funding application, ethics application, recruitment of participants, acquisition of data, statistical analysis and drafting the final manuscript. SM was responsible for the recruitment of participants at site 2 and acquisition of data. NS was responsible for assisting in the College of Optometrists funding application, editing the final manuscript, administrative, technical or material support and supervision. PJM was responsible for assisting in the College of Optometrists funding application and editing the final manuscript, statistical analysis, administrative, technical or material support and supervision. AD-N was responsible for the initial design and concept of the study, NIHR Biomedical Research Centre grant application, ethics application, overseeing the study, editing the final manuscript, statistical analysis, administrative, technical or material support and supervision. EMMcV and SML had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. All authors contributed to analysis/interpretation of data, drafting of the manuscript and critical revision of the manuscript for important intellectual content.
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PJM: Heidelberg Engineering & LKC Inc. (research support). NS: The Moorfields Acuity Chart (co-inventor) and COMPlog Clinical Vision Measurement Systems Ltd. (research support). AD-N: Santen Inc. (medical advisor).
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McVeigh, E.M., Ludden, S.M., Mohamed, S. et al. Preliminary clinical validation of a new picture–based visual acuity test in children with amblyopia: a comparison of The Auckland Optotypes and crowded logMAR letters. Eye 36, 2341–2345 (2022). https://doi.org/10.1038/s41433-021-01840-3
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DOI: https://doi.org/10.1038/s41433-021-01840-3
