nägemishäire, mis seisneb eseme samaaegses nägemises kahes eri kohas, the seeing of a single object as double, usually resulting from misalignment of the two eyes, but sometimes due to optical faults such as variations of density and consequently of refractive index within the crystalline lens, the condition in which a single object, or the haploscopically presented equivalent of a single object, is perceived as two objects rather than one, a disorder of vision in which two images of a single object are seen (as from unequal action of the eye muscles)