Abstract: An eye-fatigue examining device and an eye-fatigue examining method capable of examining eye fatigue of a subject's eye regardless of an age of a patient are provided. The eye-fatigue examining device includes: a light quantity difference adjusting unit that increases a light quantity difference between lights respectively incident on right and left subject's eyes; a gaze direction detecting unit that detects gaze directions of the respective subject's eyes while the light quantity difference adjusting unit increases the light quantity difference; and a light quantity difference deciding unit that decides a specific light quantity difference at which a change in the gaze directions due to the increase in the light quantity difference occurs, based on the detection result of the gaze direction detecting unit.

Abstract: An eye-fatigue examining device and an eye-fatigue examining method capable of examining eye fatigue of a subject's eye regardless of an age of a patient are provided. The eye-fatigue examining device includes: a light quantity difference adjusting unit that increases a light quantity difference between lights respectively incident on right and left subject's eyes; a gaze direction detecting unit that detects gaze directions of the respective subject's eyes while the light quantity difference adjusting unit increases the light quantity difference; and a light quantity difference deciding unit that decides a specific light quantity difference at which a change in the gaze directions due to the increase in the light quantity difference occurs, based on the detection result of the gaze direction detecting unit.

Abstract: A method and apparatus for doubling and twisting a material yarn by a two-step changeover system by utilizing a pot twisting and winding device is disclosed. To produce a doubled and twisted yarn having a yarn configuration of two component yarns forming the yarn in a balanced condition, when the second step operation is carried out so as to double a primary twisted yarn of a yarn package formed in the pot by a first step operation with a yarn fed from a supply source and twist this doubled yarn while eliminating the primary twists imparted to the material yarn, the position of the bottom end of the traverse tube in the pot must be controlled so as to satisfy a particular condition D.sub.2 .gtoreq. L.sub.2, where D.sub.2 represents an inside diameter of the full size yarn package formed in the pot by the first step operation, while L.sub.2 represents a distance between the bottom end of the traverse tube and an inside bottom surface of the pot.