Showing papers on "Monocular vision published in 1980"

Visual stability and space perception in monocular vision: mathematical model.

Abstract: A deterministic model for monocular space perception is presented. According to the model, retinal luminance changes due to involuntary eye movements are detected and locally analyzed to yield the angular velocity of each image point. The stable three-dimensional spatial coordinates of viewed objects are then reconstructed using a method of infinitesimal transformations. The extraction of the movement (parallax) field from the optical flow is represented by a set of differential equations, the derivation of which is based on the conservation of energy principle. The relation of the model to retinal neurophysiology and to various aspects of visual space perception is discussed.

Cumulative effect of brief daily periods of monocular vision on kitten striate cortex.

Abstract: Eight kittens were subjected to daily 4-h sessions with vision restricted to one eye between the 4th and 9th postnatal weeks. The total duration of monocular exposure ranged from 76 to 152 h. Between monocular exposure periods, four kittens were kept in total darkness, and four experienced binocular vision under normal colony conditions. At the end of the rearing period, all experimental animals and four normally reared controls were studied by means of single-unit recording in primary visual cortex. In kittens with inter-session dark rearing, very few neurons could be driven through the deprived eye. This effect was more extreme than that observed after continuous dark rearing. Visual responses mediated by the experienced eye appeared normal. In contrast, in kittens with inter-session binocular vision, the large majority of visual cortical neurons responded to visual stimulation of either eye. A few neurons appeared to have lost their responsiveness to the deprived eye, but this effect was small. We conclude that monocular vision delivered during brief daily sessions produces a cumulative competitive inactivation of transmission in the pathway from the deprived eye to striate cortex so long as no visual stimulation occurs outside the monocular periods. Binocular visual stimulation received between sessions rapidly and almost completely reverses the effects of monocular vision.

Binocular Vision and Strabismus

Abstract: This chapter provides an overview of binocular vision and strabismus. Binocular single vision may be defined as the coordinated use of two eyes to produce a single mental impression. The law of projection of images establishes that an object that forms its image on any point in the retina is projected to a point in space directly opposite. When a distant object is viewed with both eyes, normally the visual axes are parallel, so that each fovea receives an image of the object. Grades of binocular vision are classified as simultaneous macular perception, binocular fusion, and stereopsis. Acquired incomitant squints give rise to diplopia because an image formed by the object of regard falls on the macula of one eye only. A dissimilar image falling on the macula of the squinting eye is normally suppressed to avoid seeing two different objects. Abducens nerve paralysis is the most common extraocular muscle palsy encountered, because the long intracranial course of the abducens nerve permits a large variety of pathological processes to act upon it.

Effect of field of view and monocular viewing on angular size judgements in an outdoor scene

Abstract: Observers typically overestimate the angular size of distant objects. Significantly, overestimations are greater in outdoor settings than in aircraft visual-scene simulators. The effect of field of view and monocular and binocular viewing conditions on angular size estimation in an outdoor field was examined. Subjects adjusted the size of a variable triangle to match the angular size of a standard triangle set at three greater distances. Goggles were used to vary the field of view from 11.5 deg to 90 deg for both monocular and binocular viewing. In addition, an unrestricted monocular and binocular viewing condition was used. It is concluded that neither restricted fields of view similar to those present in visual simulators nor the restriction of monocular viewing causes a significant loss in depth perception in outdoor settings. Thus, neither factor should significantly affect the depth realism of visual simulators.

Use of Vision in the Function of Hand Eye Co-Ordination

Abstract: Until recently Occupational Therapists paid lip service to the term hand eye co-ordination without serious consideration of the mechanics of that function. Analysis of the processes involved in focus following, scanning and checking does not have to be at a highly scientific level. However, some consideration of the manner in which the eye functions would be very helpful in interpreting the effectiveness with which a patient uses his eyes.

Relationship between perceptual stability, and sighting dominance.

Abstract: A study was made of perceptual stability (in binocular, right and left monocular vision) and sighting dominance. 47 female psychology students served as subjects. The intention was to verify: (1) the hypothesis of asymmetry between the two eyes in the duration of the retinal image, which is indicative of sensory dominance; (2) the existence of a relationship between the two forms of dominance. The results seem to confirm the first hypothesis. Other relationships between sighting dominance and stability of image emerged. There was a positive correlation between sighting dominance and perceptual stability in binocular vision. There appear to be significant differences in perceptual stability depending on whether subjects show right, left, or no dominance.