A Visual Illusion of Motion During Eye Closure, Volume 7, Issue 3 |
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afferent sensations amount appear backward movement binocular closure center of rotation component consciousness cornea corneal movement corresponding decrease degree of convergence direction and extent displaced image distance entoptic phenomena explain eye changes eye move eye movements eyeball fact factor field of regard finger pressure fixated object fixation positions forward movements fovea function Hence heteronymous illusions image displacements image movements image moves lateral displacement left eye length line of sight located median plane ment monocular movement varies movements occur muscles nasalward negative after-images normal rotation observed ophthalmoscopic opposite eye optic axis paresis phenomenon physiological process point of fixation possible pressure and closure pressure or closure primary position produce reflex refractive changes relation retina retinal movements retinal shifting right eye right eye's image screen socket spatial reference stimulation suction superimposed rotation tests theory third dimensional tion vergence visual field visual images winking zero point
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Page 21 - These circles with their centers, x and *', and their radii xy and x' y' are drawn on the charts, graphically representing their relations to the zero point. They are all given together in Chart I, so that comparisons among the three subjects can easily be made. The actual distances in centimeters of the centers from the zero points and the lengths of the radii are given in Table V. With the larger circle, the results for subjects i and 3 agree fairly well. The centers of the circles are above the...
Page 56 - Hermann, Handbuch der Physiologic, iii, i, 32-35. opening of the lids, external mechanical pressure, and varying internal pressure are admitted by physiological authorities.1 Miiller 2 first noticed the forward displacement due to the forcible opening of the lids beyond their normal condition, and the observation was afterward confirmed by Donders ' and Berlin.4 Donders also detected a backward displacement with eye closure. The total amount of this forward and backward displacement is from .75 to...
Page 96 - has proposed a retinal explanation, a theory formulated from some tests on the "creeping-insect" phenomenon. The theory seems legitimate in the latter case, but its extended application is hardly necessary or justifiable. The essential and general facts in regard to " autokinetic sensations" are these: (i) The fixation object is an isolated light of weak intensity; (2) the direction of the movements depends upon the position of the fixation in the field of regard. Generally the direction is peripheral...
Page 13 - I and 3 the points are crossed as it were; the right zero point is to the left of the median plane, and the left zero point to the right. With No. 2, each point is on the same side of the median plane as the eye to which it belongs. Table I gives these relations in centimeter distances on the screen, and in angular terms in reference to the eye.
Page 42 - E, fixated object. the general direction of movement, the amount of spreading being greatest in that part of the field toward which the movement is directed. The images d and / have thus moved apart, but not to the same extent as have a and c. Consequently a has not only moved more than 1, but in a slightly different direction.
Page 57 - I.5 mm., the amount apparently varying according to the position of the fixation in the field of regard. Berlin also maintains such a displacement in normal rotation, but in this case the movement was not directly observed, but inferred from his determinations on the position of the center of rotation. This inference is not generally accepted, however. As to any lateral displacement...
Page 51 - Binocular pressure, and an outward traction on the eyelids produced forward movements. Subject 4. The phenomenon did not occur for monocular closure. Binocularly, the component was forward and i to 2 inches in length. The movement was seen as a resultant, and did not seem to be a matter of interpretation. In several cases the fixated object moved forward and to the left during a partial closure, ab (fig. 7). On opening the eyes the object at first moved F,«.;.