• Title, Summary, Keyword: Stereo acuity

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Comparison of Stereoscopic Fusional Area between People with Good and Poor Stereo Acuity (입체 시력이 양호한 사람과 불량인 사람간의 입체시 융합 가능 영역 비교)

  • Kang, Hyungoo;Hong, Hyungki
    • Journal of Korean Ophthalmic Optics Society
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    • v.21 no.1
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    • pp.61-68
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    • 2016
  • Purpose: This study investigated differences in stereoscopic fusional area between those with good and poor stereo acuity in viewing stereoscopic displays. Methods: Stereo acuity of 39 participants (18 males and 21 females, $23.6{\pm}3.15years$) was measured with the random dot stereo butterfly method. Participants with stereo-blindness were not included. Stereoscopic fusional area was measured using stereoscopic stimulus by varying the amount of horizontal disparity in a stereoscopic 3D TV. Participants were divided into two groups of good and poor stereo acuity. Criterion for good stereo acuity was determined as less than 60 arc seconds. Measurements arising from the participants were statistically analyzed. Results: 26 participants were measured to have good stereo acuity and 13 participants poor stereo acuity. In case of the stereoscopic stimulus farther than the fixation point, threshold of horizontal disparity for those with poor stereo acuity were measured to be smaller than the threshold for those with good stereo acuity, with a statistically significant difference. On the other hand, there was no statistically significant difference between the two groups, in case of the stereoscopic stimulus nearer to the fixation point. Conclusions: In viewing stereoscopic displays, the boundary of stereoscopic fusional area for the poor stereo acuity group was smaller than the boundary of good stereo acuity group only for the range behind the display. Hence, in viewing stereoscopic displays, participants with poor stereo acuity would have more difficulty perceiving the fused image at farther distances compared to participants with good stereo acuity.

Discussion on Preliminary Test for Male High School Students in Gwang-ju Area (광주지역 남자 고등학생들의 예비검사에 대한 고찰)

  • Ryu, Geun-Chang
    • Journal of Korean Ophthalmic Optics Society
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    • v.12 no.4
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    • pp.95-99
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    • 2007
  • This study performed apreliminary test with male high school students in Gwangju metropolitan city in order to determine visual function information of high school students. For the items in this preliminary test, there were inquiry, test for long distance unaided visual acuity, pinhole visual acuity test, colour vision test, cover test and stereo test. Most complaint related to eye was about blurred vision (28.4%) and over 90% of subjects had one or more, and among them, over 50% appealed two or more complaints. 76.1% of all subjects showed less than 0.7 in unaided distance visual acuity. In pinhole visual acuity test, 98% had an improved unaided pinhole visual acuity and most of them experienced an improvement and 2% had no change or dropped. The students with normal stereoscopic vision test were 85.6% and the students under normal range were 14.4%. In colour vision test, 7.9% of them were protanomaly and deuteranomaly and none of them had trichromasy and total color blindness. In cover test, it showed 30.2% of orthophoria, 8.2% of esophoria and 61.5% of exophoria, and none of them had strabismus.

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Effect of Overcorrection (-)Lens on Stereo-acuity and Angle of Deviation in Intermittent Exotropia (간헐외사시에서 과교정 (-)렌즈가 입체시 및 사시각에 미치는 영향)

  • Kim, Young Cheong;Park, Sang Woo
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.3
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    • pp.305-311
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    • 2013
  • Purpose: This study was conducted to evaluate the effect of prescription of overcorrection (-) lens, which is the one of the non-surgical treatments, on stereo-acuity and angle of deviation in intermittent exotropia. Methods: Twenty four children with intermittent exotropia were enrolled from October 2011 to December 2011. The angle of deviation(${\Delta}$), stereo-acuity (arcsec), monocular and binocular visual acuity (BVA, LogMAR), control of exodeviation and fusional ability using Worth 4 dot test were evaluated at near (33 cm) and far (6 m), under the overcorrecting (-)lens of -1.00, -.00, and -.00 D. Results: As a baseline finding, the angle of exodeviation was $20.9{\pm}9.7$ at near and $23.0{\pm}7.5$ at far. The angle of exodeviation at near decreased to $18.5{\pm}10.0$ (p<0.01), $15.8{\pm}9.0$ (p<0.01), $14.0{\pm}9.1$ (p<0.01) compared with baseline angle of exodeviation at near, as increasing diopters of (-) lens from -.00 D, -2.00 D and -.00 D, respectively. The angle of exodeviation at far also decreased to $21.4{\pm}5.2$ (p=0.01), $19.6{\pm}6.3$ (p<0.01) compared with baseline, as increasing minus lens from -2.00 D and -3.00 D, respectively. However, BVA, control of exodeviation, fusional ability and stereo-acuity showed no significant decrease despite of increasing diopters of (-)lens. Conclusions: The prescription of overcorrection (-)lens is an effective therapeutic method in intermittent exotropia which can reduce the near and far angle of exodeviation, and binocular visual acuity and stereo-acuity maintained without significant decrease despite of application of overcorrection (-)lens.

An Evaluation of Clinical Performance on the Aniseikonia Corrective Spectacles (부등상시 보정안경의 임상성능 평가)

  • Noh, Kyou-Tae;Kim, Hak-Jun;Mah, Ki-Choong
    • The Korean Journal of Vision Science
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    • v.20 no.3
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    • pp.327-340
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    • 2018
  • Purpose : To evaluate the clinical performance on the aniseikonia corrective spectacles. Methods : Aniseikonia corrective spectacles were prescribed on 30 anisometropes (12 males and 18 females, mean age 23.7 yrs.). Corrected visual acuity (LogMAR), spectacle magnification, amount of aniseikonia, and stereo-acuity were measured by habitual spectacles and aniseikonia corrective spectacles, respectively. The subjective satisfaction was measured by questionnaire after wearing the spectacles for 1 week. Results : The difference of spherical equivalent power between dominant and non-dominant eyes in aniseikonia corrective spectacles was increased compared to the case of habitual spectacles, but the difference was not significant (0.22D, p=0.41). The difference in monocular corrected visual acuity (LogMAR) has significantly decreased (0.04, p=0.03) and binocular corrected visual acuity (LogMAR) has significantly improved (0.07, p=0.00). The difference of spectacle magnification between right and left eyes of aniseikonia corrective spectacles (1.23%) was significantly lower than the difference in habitual spectacle (2.63%)(p=0.00). Stereo-acuity was improved by 46 seconds of arc in the aniseikonia corrective spectacles, and subjective satisfaction of aniseikonia corrective spectacles was significantly improved than habitual spectacles. Thick edges of lenses and ugly in appearance were found to be the main improvements. Conclusions : It was found that aniseikonia corrective spectacles provide a visually comfortable and satisfying life for the anisometropes. Additionally, this study could suggest a practical application for clinical purposes related to the prescription and dispensing of aniseikonia corrective spectacles.

The Effects of Sports Vision Training on Baseball Player's Visual Performance and Baseball Records (스포츠비젼 트레이닝이 시기능 및 야구성적에 미치는 영향)

  • Lee, Min-A;Oh, Jae-Man;Jeong, Ju-Hyun
    • Journal of Korean Ophthalmic Optics Society
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    • v.15 no.1
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    • pp.87-97
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    • 2010
  • Purpose: The purpose of this study is to investigate the effects of sports vision training on baseball player's visual performance and baseball records. Methods: All subjects were 21 males of high school baseball players, and they participated on eight weeks of sports vision training program. Pre- and post- test results were obtained for static and dynamic visual acuity, static and dynamic stereo acuity, distance and near phoria, fusional reserves, near point of convergence, contrast sensitivity, visual-reaction time. Results: Statical analysis indicated significant improvement in most of mentioned visual variables and baseball records (p<0.001). Conclusions: It can be concluded that the sports vision training program improves visual skills of baseball players, which could lead to improvement in the baseball records. Vison training will be a promotor for baseball player to enhance their performance if proper test instruments and training course is supplied.

The Development of Stereotest using Gabor Images in 3D Environment: An Explorative Study (3D 환경에서 가보 영상을 이용한 입체 시력 검사도구의 개발: 탐색적 연구)

  • Kham, Keetaek
    • Journal of Broadcast Engineering
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    • v.20 no.6
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    • pp.901-911
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    • 2015
  • Many studies tried to develop a 3D display based stereo test as a substitute for the conventional stereo test. Although many 3D monitor based stereo tests have various advantages over the conventional stereo tests with printed stimuli, they have a crucial limitation in manipulating disparity. The least value for disparity manipulation is one pixel, which is too big to screen the normal stereo acuity in pc environment with a short viewing distance. In this explorative study, a Gabor image was employed as a test stimulus, because its position can be manipulated by changing its phase information, which allows sub-pixel manipulation for disparity. Instead of employing the methods of the conventional stereo tests where measurement was made only once for each of a wide range of disparity values, 10 replications were administrated for each of 6 disparity levels. The results from the test using Gabor images were compared with those using random dot stimulus because the latter stimulus was exactly the same as that of the conventional stereo test. The correlation coefficient between two tests was found to be moderate. After one month later, the whole test was repeated in the same settings. The correlation coefficient between test and retest results from Gabor images was found to be as high as that from a random dot stimulus, implying high test-retest reliability. These results suggest that a Gabor stimulus could be used as a test stimulus for the valid and reliable stereo test, even in the limited condition, such as 3D environment with a short viewing distance and a condition for evaluating the stereo acuity very precisely.

Use of Piggyback Contact Lens System to GP Lens Wearers (GP렌즈 착용자에게 피기백 콘택트렌즈 시스템의 적용)

  • Kim, Yong Gil;Kim, Soo Hyun;Kim, Jai Min
    • Journal of Korean Ophthalmic Optics Society
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    • v.15 no.1
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    • pp.47-53
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    • 2010
  • Purpose: This study was performed to achieve an acceptable piggyback fit utilizing each subject's own GP lenses, in subjects with regular low myopic astigmatism. Methods: A randomized, prospective study of 15 subjects with the diagnosis of low myopic astigmatism was conducted. Nine subjects were female and 6 were male, and mean age was: 23.73${\pm}$1.68 years. Subjects were evaluated before participate on this study and then also evaluated with period of at two hours and two weeks after obtaining their lenses. All subjects were submitted to the following tests: measurement of comfort level by means of the analogical visual scale, best corrected visual acuity and over-refraction at distance. contrast sensitivity and stereo acuity. After evaluating the fit of plano soft lens, we applied each subject's own GP lens on top. Results: Vision, visual performance and satisfaction of piggyback contact lens system were stable, if not improved, for the 15 subjects when the data was compared to the patients' wear of rigid gas permeable contact lenses. Fit with a piggyback system had the same or improved comfort, visual acuity and contrast sensitivity compared to previous GP lens wear alone. The visual acuity, contrast sensitivity and stereo acuity did not show differences in relation to the studied lens type. Conclusions: These results suggest that it is possible to achieve a successful piggyback lens fitting utilizing a patient's own GP lens. The piggyback lens system satisfied the visual performance and visual requirements of this subject with GP lens alone for the correction of low myopic astigmatism.

Dynamic Visual Acuity and Dynamic Stereoacuity of Athletes and Nonathletes (운동선수와 대학생 남녀의 동체 시력 및 동적 입체시에 관한 비교 연구)

  • Lee, Min-A;Oh, Jae-Man;Jung, Ju-Hyun
    • Journal of Korean Ophthalmic Optics Society
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    • v.14 no.3
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    • pp.43-49
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    • 2009
  • Purpose: The purpose of this study was to obtain the fundamental data of dynamic visual acuity and dynamic stereoacuity. Methods: The subjects were 20 athletes (high school baseball player) and 40 nonathletes (20 male, 20 female). We assessed static visual acuity, dynamic visual acuity, static stereoacuity and dynamic stereoacuity using rotating mirror projection system and computer program. Results: Three groups had similar static visual acuity and static stereoacuity. On the other hand, the dynamic visual acuity and dynamic stereoacuity showed statistically significant differency. The mean dynamic visual acuity for athletes was 174.80${\pm}$28.70 deg/sec, 137.10${\pm}$16.54 deg/sec for male nonathletes and 111.59${\pm}$15.40 deg/sec for female nonathletes. The mean dynamic stereoacuity for athlets was 234.55${\pm}$19.64, 249.05${\pm}$8.86 for male nonathletes and 247.10${\pm}$14.89 for female nonathletes. The group of athletes had better dynamic visual acuity and dynamic stereoacuity. Conclusions: If the result of this study apply to sports, it will be very useful to improve sports performance.

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Stereoscopic Depth from 3D Contents with Various Disparity (화면 시차로부터 지각되는 3D 컨텐츠의 입체시 깊이)

  • Kham, Keetaek
    • Journal of Broadcast Engineering
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    • v.21 no.1
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    • pp.76-86
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    • 2016
  • This study was investigated whether the perceived depth was changed depending on the measurement methods. In the method of direct comparison, virtual object with one of the various binocular disparities was presented in the frontal space with LEDs which were used for depth estimation for a binocular stimulus, while in the method of indirect comparison, visual object was presented in the frontal space but the LEDs were placed rightward at the angle of 45 degree from the mid-sagittal line. In these experimental setup, the depth of binocular stimulus was directly matched that of LED in direct comparison condition. In indirect comparison condition, however, observer estimated the depth of binocular stimulus, turned one's head rightward to the array of LEDs and turned on the LED which was supposed to be the same depth as binocular stimulus. Additionally, it was investigated whether the perceived depth was different depending on observer's stereo acuity. The results showed that perceived depths measured in the direct comparison were more similar to the depth predicted from geometry than those in the indirect comparison, and that the perceived depths from observers with high stereo acuity were similar to the predicted depth from geometry those from observers with low stereo acuity. These results indicated that stereoscopic depths of the binocular stimuli would vivid and compelling when binocular stimuli was simultaneously presented with real objects in the same visual space, like a mixed reality.

Effects of Induced Dioptric Blur on Visual Acuity and Contrast Sensitivity (유발된 광학적 흐림이 시력과 대비감도에 미치는 영향)

  • Kim, Chang-Jin;Choi, Eun Jung
    • Journal of Korean Ophthalmic Optics Society
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    • v.19 no.2
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    • pp.261-270
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    • 2014
  • Purpose: To study the effect of an artificially induced dioptric blur on acuity and contrast sensitivity using the $Optec^{(R)}$ 6500. Methods: Healthy 31 subjects aged $22.90{\pm}1.92$ (male 16, female 15) who were recruited from university students with 6/6 (20/20) or better corrected visual acuity and normal binocularity. They were measured objective and subjective refraction for full correction and dioptric blur using 0.00 ~ +3.00 D (+0.50 D steps) trial lenses and trial frame. They were measured binocularly visual acuity and contrast sensitivity with the $Optec^{(R)}$ 6500 (Stereo Optical Co., Inc., Chicago, Illinois, USA) under day conditions (photopic condition, $85cd/m^2$). Results: The higher dioptric blur, the less distance visual acuity and decrease rate of visual acuity. The higher dioptric blur, the less contrast sensitivity at all frequencies, and the peak of contrast sensitivity was shifted from middle frequency (6 cpd) to low frequency (1.5 cpd). When the visual acuity was best visual acuity to 0.77, there was the peak point at 6 cpd which was normal contrast sensitivity peak point. Conclusions: If the low refractive error is uncorrected or the refractive error is inappropriate, the contrast sensitivity is decreased and the peak point of contrast sensitivity frequency is shifted abnormally though small uncorrected refractive error. So it will be considered that regular eye test and decision of refractive error correction is important.