Blind spot "fixation" in normal eyes: implications for eccentric viewing in bilateral macular disease.

Normal subjects were trained to look to the side of a small, flickering target in order to make this target disappear within the physiological blind spot of the right eye. Subsequently, subjects aimed the eye more eccentrically when the target was nearer and less eccentrically when the target was farther than when it was at the training distance of 1.5 m. Thus, the eccentric eye aiming of our subjects represented a compromise between looking to the side of the target by a constant visual angle and by a constant lateral extent. We propose that patients who lose central vision bilaterally may similarly err in trying to aim the diseased macula to one side of targets by a constant visual angle, impeding their ability to use a single, nonfoveal region effectively.