INTEGRATION OF LOCAL ORIENTATION IN STRABISMIC AMBLYOPIA

In order to investigate the processes which integrate local orientatio n information in observers with strabismic amblyopia, we measured cont rast thresholds for discriminating the global orientation of a pattern (3 ''bars'') comprised of Gabor patches. We found that in both eyes o f amblyopic observers, as has been reported for normal observers [Saar inen, Levi & Shen (1997) Proceedings of the National Academy of Scienc es USA, 94, 8267-8271], there is an approximately two-fold enhancement of contrast sensitivity when the global and local orientations are al igned (relative to mixed orientations), and a smaller enhancement when the global and local orientations are orthogonal. This orientation de pendent enhancement occurs despite substantial losses of contrast sens itivity. These results suggest that the integration processes in the a mblyopic eye that operate to enhance detection are essentially intact. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.