DE2422553

To induce the eyes to deaccommodate during examination by an instrument having an optical system aligned with one eye, a target viewable through an eyepiece is presented to and aligned with the other eye. The target is adjusted until clearly visible and then moved straight away from the other eye to appear to recede to induce both eyes to deaccommodate. A pair of eyepieces are arranged on each side of the optical system to register with the eye not being examined, and a horizontally movable slide carrying a slidable target is operated by knobs for aligning the slide with the eye and moving the target along the slide. Alternatively, a binocular system can be used with a slightly blurred target presented to the eye not being examined, and a visibly lighted, sharp image target presented to the eye being examined and arranged to be blurred to induce de-accommodation of the examined eye.