A new test of contour integration deficits in patients with a history of disrupted binocular experience during visual development

Ilona Kovács, Uri Polat, Philippa M. Pennefather, Arvind Chandna, Anthony M. Norcia

Research output: Contribution to journalArticlepeer-review

108 Scopus citations


Previous studies have suggested that the integration of orientation information across space is impaired in amblyopia. We developed a method for quantifying orientation-domain processing using a test format that is suitable for clinical application. The test comprises a graded series of cards where each card includes a closed path (contour) of high contrast Gabor signals embedded in a random background of Gabor signals. Contour visibility in both normals and patients with histories of abnormal binocular vision depends jointly on the spacing of elements on the contour as well as background element density. Strabismic amblyopes show significant degradation of performance compared to normals. Small but significant losses in sensitivity were also observed in a group of non-amblyopic strabismus patients. Threshold measurements made with contrast reducing diffusers indicated that the amblyopic loss is not due to the reduced contrast sensitivity of the amblyopic eye. An abnormal pattern of long-range connectivity between spatial filters or a loss of such connectivity appears to be the primary source of contour integration deficits in amblyopia and strabismus. (C) 2000 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)1775-1783
Number of pages9
JournalVision Research
Issue number13
StatePublished - 16 Jun 2000
Externally publishedYes

Bibliographical note

Funding Information:
The authors thank Ákos Fehér for developing the algorithm and software necessary for the generation of the contour cards, and Jochen Braun for making available his contour generating algorithm. This paper was supported by grants from the J.S. McDonnell Foundation 9560 to I.K., EY06579 to A.M.N. and a Rachel C. Atkinson Fellowship to U.P.


  • Amblyopia
  • Contour integration
  • Grouping
  • Spatial interactions
  • Strabismus


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