Ocular dominance, as measured in sighting tests, involves a temporary suppression of the input from the non-dominant eye in order to avoid diplopia. Amblyopia ex anopsia may be viewed as a long term suppression of the input from one eye for the same reason. In the absence of anisometropia, paralysis of extra ocular muscles, or other factors which would tend to determine which eye would manifest suppression, the non-dominant sighting eye should be more likely to develop amblyopia given the presence of strabismus. A sample of 258 amblyopes supports this prediction based on the population norms for sighting dominance.