Abstract
Many ophthalmic instruments use fixation targets, which are marks at which a subject gazes continuously to hold his or her eyeball or line of sight in a fixed position. In research and development work at Fuji Xerox on optical instruments for use with the eyeball, it became necessary to keep the subject’s line of sight steady for an extended period of time. With existing fixation targets this proved difficult: the targets were hard to recognize and the line of sight tended to wander quickly. In this study quality engineering was used to test quickly new ideas for the design and display of fixation targets by evaluating temporal variations in the subject’s gaze position as a dynamic characteristic. The target design and display method became control factors in experiments using an L12 orthogonal array. In consideration of the varying signal levels and effective divisor in different experiments, the evaluation was carried out with the energetic S/N ratio. This led to the development of a fixation target and display method that improved gaze stability by approximately a factor of two.