Evidence map›Paper›PMID 42090277›Full record

ArticleInvestigative ophthalmology & visual science2026

Development of Crowding Distance in Children Is Faster and Later Than Visual Acuity and Better Predicts Reading Performance.

Sarah J Waugh, Monika A Formankiewicz, Leticia Álvaro, Denis G Pelli

Abstract read
In one paragraph

Article in Investigative ophthalmology & visual science, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

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1citing papers in PubMed
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1 · What the graph read from it

What it found

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2 · The registry

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3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

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4 · The record

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5 · Who and what money

Authors and funding

4 authors.

Sarah J WaughCentre for Vision across the Life Span, School of Applied Sciences, University of Huddersfield, West Yorkshire, United Kingdom.
Monika A FormankiewiczResearch Centre for Better Living, School of Psychology, Sport and Sensory Sciences, Anglia Ruskin University, Cambridge, United Kingdom.
Leticia ÁlvaroDepartamento Psicología Experimental, Procesos Cognitivos y Logopedia, Universidad Complutense de Madrid, Madrid, Spain.
Denis G PelliPsychology Department, New York University, New York, New York, United States.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Purpose: Visual crowding is a failure of object recognition due to nearby clutter. Crowding distance (CD) is the threshold spacing for identification of a target among flankers. Visual acuity (VA) is the smallest recognizable letter size. In normal adult vision, CD worsens more than VA with increasing eccentricity and is worse than VA in central vision of strabismic amblyopia. CD is not measurable in mature central vision with standard optotypes but is with tall, skinny optotypes. We reveal developments of CD and VA in children and consider their impacts on teacher-assessed reading performance. Methods: VA (isolated Sloan letter size threshold) and CD (Pelli optotype spacing threshold) were measured in 227 normal, healthy children aged three to 11 years and 40 adults. CD was measured for trigram and repeated arrangements. Teacher-assessed reading indicators for 200 of these children were converted to a study reading indicator (SRI). Results: From age three years, VA improves 1.4×, reaching near-adult levels at six years (P > 0.05). CD reduces 4.8×, reaching near-adult levels at eight years (P > 0.05). Correlations between vision measures and SRI were higher for CD than VA (CD-trigram: r = -0.68; CD-repeated: r = -0.67; VA: r = -0.37; all P < 0.0001). Removing age shows CD, but not VA, matters for reading (CD-trigram: r = -0.24, P = 0.00065; CD-repeated r = -0.25, P = 0.00049; VA: r = -0.13, P = 0.075). Conclusions: Crowding develops more quickly and matures later than acuity and is significantly linked to children's reading performance, unlike acuity. Crowding distance measures may be more sensitive diagnostically than acuity for detecting exaggerated crowding found in strabismic amblyopia and may help identify children who struggle to read.

Indexed as

ReadingVisual AcuityAdultAmblyopiaChildChild, PreschoolFemaleHumansMale

Identifiers

PMID42090277
PMCPMC13170733

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.