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Visual Crowding in Young Children

1986; Springer Nature (Netherlands); Linguagem: Inglês

10.1007/978-94-009-4263-9_27

0303-6405

Janette Atkinson, E. Pimm‐Smith, Chris Evans, G. F. A. Harding, Oliver Braddick,

Neural and Behavioral Psychology Studies

‘Visual crowding’ or ‘lateral masking’ is the deleterious effect nearby contours have on the recognition and identification of symbols or letters. Its magnitude has often been estimated by comparing single optotype acuity with acuity for multiple arrays. In adults, the effect was described for peripheral vision some time ago (Ehlers, 1936; Woodworth and Schlosberg, 1954; Bouma, 1970) with a smaller similar effect being described for the fovea (Flom et al., 1963). In a number of studies of amblyopes a large crowding effect has been described (Stuart and Burian, 1962; Oliver and Nawratzki, 1971; Hilton and Stanley, 1972; Tommilla, 1972; Weiss, 1973; Youngson, 1979; Beyerstein and Freeman, 1977). To assess the degree of abnormality in amblyopes it is necessary to know the size of the crowding effect in children with normal vision. Here we report two studies using novel tasks to assess crowding in children with normal vision. The results of this study are to serve as a baseline against which to measure abnormality. Relatively naive adults have also performed the tasks for comparison purposes.