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Publications

Journal Article Ahead of print

PubMed: 42407234 DOI: 10.1016/j.visres.2026.108873

Impact of crowding on visual appearance and performance in amblyopia.

Vision Res 247:108873

Authors: Ângela Gomes Tomaz, Wolf Harmening, Dennis M Levi, Bilge Sayim

Affiliations

  • Herbert Wertheim School of Optometry & Vision Science, University of California Berkeley, Minor Hall, 380 Minor Ln, Berkeley, CA 94720, United States of America.
  • Department of Ophthalmology, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
  • Herbert Wertheim School of Optometry & Vision Science, University of California Berkeley, Minor Hall, 380 Minor Ln, Berkeley, CA 94720, United States of America.
  • Laboratoire de Sciences Cognitives et Psycholinguistique (LSCP), Département d'Études Cognitives (DEC), École normale supérieure (ENS), CNRS, PSL University, 29 rue d'Ulm, 75005 Paris, France.

Abstract

Individuals with amblyopia have been reported to perceive stimuli as distorted with the amblyopic eye, and to have stronger foveal crowding than controls without amblyopia. Previous studies on visual appearance in amblyopia often lacked a control group and did not adjust stimulus size to account for visual acuity deficits. Here, we investigated whether observers with amblyopia perceived stimuli as more distorted and whether foveal crowding influenced visual appearance more strongly than in controls, while controlling for visual acuity differences. Isolated and flanked target letters were presented foveally to the dominant/fellow and non-dominant/amblyopic eye. Stimuli were scaled relative to each eye's acuity threshold and presented at 1.0× and 1.5× threshold size. Observers replicated target appearance by selecting squares on a novel grid interface. Results showed that accuracy, structural similarity (SSIM) and perceived similarity (PSS) were lower for observers with amblyopia compared to controls (Group), for small compared to large stimuli (Size), and for flanked compared to isolated targets (Crowding). Interestingly, a significant interaction between Group and Crowding was observed only for accuracy and SSIM, but not for PSS. These results showed group differences despite controlling for acuity, suggesting that factors beyond visual acuity, such as stronger foveal crowding, contribute to visual appearance differences in amblyopia compared to controls.

MeSH

Eye, Vision, Ocular, Amblyopia, Visual Acuity, Crowding