VARIATION OF VISUAL PERCEPTION OF SPATIAL OBJECTS AND DEVELOPMENT OF PERCEPTUAL APTITUDE

Clarification of the manner in which a driver perceives visual data in motion while driving, especially due to varying perception of static and mobile phenomena, has great implications for human safety. This report brings together relevant studies in this area made over the past twelve years. (1) The relationship between mode of perception of moving objects, objects in space, and traffic accidents. a) Visual acuity vis-a-vis a moving target (DVA: kinetic visual acuity) tends to decline as speed is increased. And it is seen to differ sharply with the individual. This decrease of powers is not a realized one. KVA diminishes irrespective of a subject's visual acuity with regard to a static object. Thus, more so than with SVA, it is difficult to surmise KVA. Decline of KVA results in communication of mistaken data to the driver and is an important factor in causing accidents. b) The visual field for discerning an existing spatial target is far more limited than the driver would believe. The further removed the target is in space, conversely, the less the field of vision. And the faster the speed of the vehicle, the more the field shrinks. c) Most freeway calamities may be laid to changing perception of speed due to many moving stimuli attaining the retina. (2) The discrepancy between physiology of KVA and space perception, and the visual perception mechanism for a static target is in the mode of accommodation and sensory mechanisms at the retina level or within the central nervous system itself. a) Accommodation to a spatial object is slow and unsteady. Accommodation to a mobile object is faster. Recognition of a moving object is accomplished through very minutely accommodative oscillation. b) Retina perceptual ability varies from part to part, with the parafovea able to view most clearly. c) It is the parafovea which visually "retrieves" moving objects. d) Accommodative powers are quickest at the moment when a visual object impinges upon the parafovea. e) Amplitude of accommodation with subjects of good KVA may be increased gradually with regard to approaching objects. Persons of poor KVA can be increased levelwise. The accommodation time of subjects with fine KVA is short. f) Visual perception ability was determined as follows: 1) Criteria of perception is the ability to distinguish clearly an object directly in front of the viewer and approaching same. 2) For perceptual value, a low number represents the visual threshold angle from which two points may be distinguished. 2) Aptitude is seen from ability of persons to recognize various moving objects. (3) Aptitude is seen from ability of persons to recognize various moving objects. (3) KVA as an indication of aptitude. a) A visual acuity measuring device was constructed. Evaluative criteria were determined. Using this instrument, examinations were made of some 3000 persons with an accident history. A follow-up investigation conducted on a driver group in a given firm indicated that an aptitude test effectively could preclude accidents. (4) Relation between eye disorders, KVA and aptitudinal development. A strong connection is seen between accidents and persons with ocular disorders but yet unaware of their failing powers. As a result of examining persons of slight trouble not affected as to KVA, it was noted that the majority were affected in great degree as to KVA. It grew clear that occasionally there were selective instances of KVA affected by certain ocular diseases. (Diffuse superficial keratitis, early stage cataracts, refractive errors, accommodative aesthenopia, eye irregularities, etc. Of these latter, especially with muscular imbalance, KVA in both eyes was markedly affected. Treatment of ocular difficulties brought about increase in KVA. It can be seen then, that even slight ocular impairment can not be made light of. Improvement would redound to developing driver competence, thus providing a great deterrent to accidents.

  • Corporate Authors:

    Japanese Ophthalmological Society

    5-2-chome, Kanda-Surugadai, Chiyoda-ku
    Tokyo,   Japan 
  • Authors:
    • SUZUMURA, A
  • Publication Date: 1971-9

Language

  • Japanese

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 33 p.
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00263314
  • Record Type: Publication
  • Source Agency: National Safety Council Safety Research Info Serv
  • Files: TRIS
  • Created Date: Nov 27 1974 12:00AM