• Korean Journal of Cognitive Science
• /
• v.16 no.4
• /
• pp.243-254
• /
• 2005

Pulfrich effect implies the possibility that motion information is processed by the system that processes depth information, and this possibility by supported by various neurophysiological studies. Although Pulfrich effect is processed by the system that processes binocular disparity, the representative depth information, there has not been a psychophysical research to determine the characteristics of the interaction between Pulfrich effect and binorular disparity using a stimulus containing the two information sources. Present research examined the characteristics of the interacation between Pulfrich effect and binocular disparity by nenuring the depth and rotation direction of a rotating cylinder comprised of random dots under two different conditions: 1) consistent rendition where the Pulfrich effect and binocular disparity depth the depth and rotation direction of the cylinder in a consistent manner 2) inconsistent rendition where they did not. , The perceived depth of the cylinder in the consistent condition was larger than that in disparity/Pulfrich effect only condition. Interestingly, the perceived rotation direction of the cylinder in the inconsistent condition was modulated by the relative strength of the disparity and the Pulfrich effect. These results imply that binocular disparity and Pulfrich effect are processed by a common neurophysiological methanism.

• Korean Journal of Cognitive Science
• /
• v.13 no.2
• /
• pp.37-45
• /
• 2002

Despite dynamical retinal image changes caused by pursuit eye movements, we usually perceive the stable spatial properties of the environment suite successfully Helmholtz and his followers have suggested that the visual system coordinates the retinal and extraretinal eye position information to represent the spatial properties of the environment. However. there have been a significant amount of researches showing that this kind of mechanism may not operate perfectly, and the pursuit eye movement employed in those researches were limited to conjugate eye movements. When an observer tracks an object moving away from the observer with his/her eyes. the two eyes rotate in opposite direction. and this kind of disjunctive eye movement may produce undesirable binocular disparities for the objects in the background. The present study examined whether the visual system compensated for the undesirable binocular disparities caused by disjunctive eye movements with extraretinal eye position information. Although the target object was presented frontoparellely to the subjects. the subjects reported that the object was slanted toward (or alway from) them in consistent with the undesirable binocular disparities produced by the disjunctive eye movements. These results imply that the visual system may not perfectly compensate for the undesirable binocular disparities with extraretinal eye position information.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.1
• /
• pp.121-125
• /
• 2009

Purpose: This study has been conducted to know the prevalence of anisometropia and corneal refraction, accommodative response of myopic anisometropia. Methods: The study subject were 67 persons who myopic anisometropia of at least 1.00D, from among 808 total subject without ophthalmic diseases history from age 5 to 89 and the test were used to examine with both eyes open-view autorefractometer (NvisionK-5001). Results: The case which anisometropia were 85(10.5%) persons and myopic anisometropia were 67(78.8%) persons among the anisometropia. Difference between higher myopic eye and lower myopic eye were -1.22D${\pm}$0.94 in spherical equivalent, -0.25D${\pm}$0.72 in accommodative response, 0.04D${\pm}$0.68 in corneal refraction. In addition, the same case of both eyes accommodative response were 33(49.3%) persons, the great case of lower myopic eye accommodative response were 25(37.3%) persons and the great case of higher myopic eye accommodative response were 9(13.4%) persons. Conclusions: Myopic anisometropia was not affected by corneal refraction and both eyes difference of spherical equivalent was less as compared with both eyes difference of accommodative response.

• Journal of the Korea Convergence Society
• /
• v.10 no.5
• /
• pp.103-110
• /
• 2019

The present study investigated the effects of AD on stereoscopic vision. Sixty participants (20 AD patients, 20 mild cognitive impairment patients, 20 healthy elderly controls) participated in the study. Two cubes, one on the left and the other on the right of the center of the monitor, appeared at varying distances from the observer with their relative distances controlled in two disparity conditions (absolute vs relative disparity) combined with two disparity directions (crossed vs uncrossed disparity). Participants identified the object that appeared closer to them. Results demonstrated comparable performance with all three groups performing accurately, suggesting that the effect of AD on stereopsis is negligible. Discussion focused on brain pathology affected by AD involving high level visual processing.

• Korean Journal of Cognitive Science
• /
• v.22 no.3
• /
• pp.235-254
• /
• 2011

Two experiments were conducted to investigate the impact of binocular disparity information on Neon color spreading (NCS). The stimuli was the modification of Ehrenstein figure used by Redies and Spillmann(1981); inner and outer segments were achromatic and middle segments was chromatic. In experiment 1, the effect of binocular disparity was tested in each segment that were divided inner, middle and outer segments. In experiment 2, the impact of added segments that were put in different depth place were tested. The results showed that the segments on same place were, the clearer the NCS was. Consistent with the previous studies, the effect of color segment in front or in behind was not appeared. The case of added segments, regardless of added segments were placed either front or behind, the NCS was reduced. But the effect of added outer segments was more affect then added inner segments. This results were suggested that NCS could be affected by depth information but more affected by stage of before depth processing.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.4
• /
• pp.555-560
• /
• 2013

Purpose: The aims of this study were to investigate the stereoacuity and subjective symptoms of aniseikonia with prescription of the size lens. Methods: Participants were myopic anisometropia patients with the binocular refraction difference between 1.75 D~3.50 D. Inclusion criteria of participants were no ocular pathology, no amblyopia, more than 1.0 of corrected visual acuity. With fully corrected spectacles and a correction with the size lens, Awaya aniseikonia test and Randot Stereo test were conducted respectively. In addition, subjective symptoms were also examined using questionnaire. Results: As the anisometropia increased, the aniseikonia increased. Under the anisometropia with same refractive correction was different for each individual. The prescription of size lens caused less aniseikonia than the general prescription of glasses. In addition, prescription of the size lens improved stereoacuity and relieved the symptoms of asthenopia. Conclusions: The prescription of size lens that can correct aniseikonia with prescription of glasses can improve stereoacuity and reduced asthenopia.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.4
• /
• pp.71-75
• /
• 2009

Purpose: This study was designed to investigate the condition of refractive correction and heterophoria and monocular pupillary distance on myopic elementary school children wearing glasses in Gwangju city. Methods: Subjective refraction and objective refraction were examined after investigating heterophoria and monocular pupillary distance on 145 (290eye) elementary school children wearing myopia-corrected glasses. Results: 1. Anisometropia > 2.00 D was present in 4 children (3%). 2. 9 anisometropia (47%) were present in 19 undercorrected visual acuity boy wearers. and 16 anisometropia (64%) were present in 25 undercorrected visual acuity girl wearers. 3. Among the 67 myopic glasses boy wearers, the distance between optical centers was coincided with the pupillary distance in 30% (Oculus Uterque), and discrepant in 70% (Oculus Uterque). Among the 78 myopic glasses girl wearers, the distance between optical centers was coincided with the pupillary distance in 23% (Oculus Uterque), and discrepant in 77% (Oculus Uterque). The mean optical center distance was longer than the pupillary distance on both boy and girl wearers 4. The result of measured heterophoria revealed 14% for orthophoria, 63% for exophoria, 23% for esophoria at far distance and 10% for orthophoria, 76% for exophoria, 14% for esophoria at near distance. Conclusions: Correct refractive test and monocular pupillary distance must be examined because incorrect refractive test and pupillary distance induce asthenopia and heterophoria.

• Korean Journal of Cognitive Science
• /
• v.10 no.3
• /
• pp.17-28
• /
• 1999

Systematic distortions in perceived 3-D shape were obtained for elliptical and parabolic stereoscopic surfaces viewed at different distances under full and reduced cue conditions. In both conditions of Experiments 1 and 3, elliptical hemi-cylinders a appeared near veridical at the 45 cm viewing distances and flattened up to 74% of veridical at 135 cm. In Experiment 2, under full cue conditions, parabolic hemi-cylinders a appeared stretched to 118% of veridical at 45 cm, near veridical at 90 cm, and flattened to 85% of veridical at 135 cm. Under reduced cue conditions parabolas appeared flatter overall: veridical curvature was obtained at 45 cm viewing distance with flatness increasing to 68% of veridical at 135 cm. Results support a scaling explanation of perceived 3-D shape from disparity and rule out the alternative hypothesis that disparity curvature, an optical invariant, provides information for the direct perception of 3-D s shape.

• Journal of Korean Ophthalmic Optics Society
• /
• v.12 no.3
• /
• pp.137-142
• /
• 2007

The purpose of this study was to investigate sole effect of therapy of spectacles correction on the refractive amblyopia. Spectacles were prescribed to give the same effect as the occlusion therapy undercorrecting in the case of hyperopia, and effectiveness of the therapy was compared with occlusion therapy without additional prescription. The results can be summarized as follows: 1. The higher anisometropic power was the lower initial visual acuity was. 2. Anisometropic power did not influence final visual acuity. 3. The latter beginning time of therapy was the higher astigmatism was. 4. Therapy of spectacles correction on the hyperopic amblyopia was quite effective.

• Journal of Korean Ophthalmic Optics Society
• /
• v.8 no.2
• /
• pp.71-76
• /
• 2003

This study was performed to survey dioptric differences between the refractive states of both eyes from 1,100 patients who were given their prescriptions in spectacles. The differences were obtained by using dioptric power matrix. The prevalence of anisometropia was 96.9% for isoanisometropia, 2.9% for simple anisometropia, 0.2% for antimetropia. Spherical anisometropia was 22.1%, cylindrical anisometropia was 10.9%, spherocylindrical anisometropia was 46.5%, and no anisometropia was 20.5%. Anisometropia was more in thirties and forties than in other groups. In distribution of only spherical diopter differences, 76.1% were less than 0.50D, 91.7% were under 1.00D, only 2.5% were over 2.00D. In cylindrical diopter differences alone, 93.3% had under 0.50D, 1.7% had more than 1.00D. In spherocylindrical anisometropia, 52.8% were less than 0.50D, 78.6% were under 1.00D, 5.1% were more than 2.00D. In axis differences, with-the-rule type was 29.9%, against-the-rule type was 29.8%, oblique type was 40.3%.