To examine the amount of defect of stereopsis in experimentally induced anisometropia of various value and type.20 healthy adults without significant refraction error or anisometropia and with full stereopsis were examined. They all undergone Titmus stereotest (circles) after they had experimentally induced anisometropia with the use of trial lenses. Mean values of stereopsis in arc sec. were calculated for each value of anisometropia.The largest defect of stereopsis was noted in spherical hypermetropia. In all kinds of refraction error the critical value for almost complete loss of stereopsis was 3D plus. Generally, the same values of anisometropia in sphere result in slightly more severe loss of stereopsis than in cylinder.