Accommodation and stereoacuity

Stereoacuity and resolution acuity were measured (1)through apertures set at various distances from O and (2) through plus lenses producing an accommodative error for the target equal to that produced by the presence of the apertures. Stereoacuity was degraded by the apertures but not by the lenses, whereas resolution acuity was degraded by the lenses but not by the apertures. Although stereoacuity progressively declined with decreasing target distance, it did not change significantly if accommodation remained constant. The decline of stereoacmty in the water ts attributed to increased accommodation resulting from different sources and to a “Ganzfeld” effect of the typical underwater scene.