Previous reports have described suppression scotomas, suppression varying with the type of strabismus and suppression confined to one half of the retina (hemiretinal suppression). Our findings show that suppression in all varieties of strabismus, with the exception of the monofixation syndrome, involves the whole of the visual field of the deviating eye except for its monocular temporal crescent. In the monofixation syndrome our findings show a small central suppression scotoma involving the fovea but leaving the rest of the visual field of the deviating eye unsuppressed. We could find no evidence to support the concept of hemiretinal suppression but found evidence to support the presence of a trigger mechanism for suppression which operates on a hemiretinal basis.