• Journal of Korean Ophthalmic Optics Society
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• v.20 no.4
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• pp.511-518
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• 2015

Purpose: The purpose of this study is to evaluate correlation between convergence insufficiency and concentration by evaluating attentiveness in children who have convergence insufficiency symptoms. Methods: The CISS survey and examination for the near point of convergence were conducted to 74 in children aged 12 to 13 years in order to divide them into a normal binocular vision (NBV) and a convergence insufficiency (CI) group. The attentiveness examination was used to all subjects to figure out their emotional problems, hyperactivity and impulsiveness problems, and managerial or functional problems with a 5-point scale. Correlation between convergence insufficiency-related symptoms included in CISS and attentiveness problems was analyzed. Results: there were 29 children (39.2%) in the CI group, the mean scores of CISS of the NBV and CI group were $5.91{\pm}3.69$ and $18.31{\pm}7.00$ each (p<0.001). On the survey of CISS symptoms, children in the CI group frequently expressed such symptoms as eye fatigue, loss of attentiveness, blurry vision, and forgetting the line they have been reading. In the attentiveness examination, the CI group ($74.83{\pm}9.83$) gained higher scores in problematic concentration than the NBV group ($46.80{\pm}11.30$). Convergence insufficiency had significantly positive correlation with total attentiveness (r=0.798). Conclusions: In elementary school students, it has been found that when perceived symptoms related with convergence insufficiency are more serious, problematic attentiveness gets serious, too.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.37-42
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• 2009

Purpose: There is uncertainty if the vergence facility would provide clinically significant supplementary information to the fusional vergence measurements. The purpose of this study was to determine the relationship between vergence facility and fusional vergence in a group of symptomatic subjects. Methods: A total of 114 symptomatic subjects aged 9 to 13 years, who passed the vision screening test, participated in this study. Vergence facility was measured with 8$\Delta$ BI/8$\Delta$ BO flipper lenses and a suppression control target, the 20/30 letter line on Vectogram 9 (Bernell, USA). Near fusional vergence was measured with a single 20/30 vertical line target by Von Graefe technique. In order to avoid excessive convergence stimulation, negative fusional vergence (NFV) range (blur, break and recovery) was measured followed by positive fusional vergence (PFV) ranges (blur, break and recovery). Results: Pearson correlations were calculated and showed no correlations between vergence facility and any of fusional vergence measurements (p>0.05). Also, there were no significant differences of vergence facility measurements on the compensating vergence that passed or failed Sheard and Morgan's criterion for comfortable vision (p>0.05). Conclusions: There was no correlation between vergence facility and fusional vergence among symptomatic subjects. Hence, both vergence facility and fusional vergence should be assessed for those with binocular dysfunction in order to make an accurate diagnosis and management plan.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.83-87
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• 2007

This study was classified and compared astigmatism's refractional abnormal degrees with visual acuity state of full correction which turned on axises of only 5 degree, 10 degree, and 15 degree. Subjects of this study were 57 college students (114 eyes) who had neither eye diseases nor binocular abnormality, were from their twenties to fifties, with myopia. It appeared that 30.8% of subjects who had astigmatism wore glasses with wrong axis of astigmatism. After accurate correction of the visual acuity and degrees of astigmatism, when we moved to corrected axises at 5 degree, 10 degree, 15 degree, failure of visual acuity with one line or more were 56.1%, 84.2%, 93.8%, respectively. When we comapre the completely-corrected visual acuity with the visual acuity with dricted axes, the bigger the width of visual acuity's weakness was the bigger the drifted angle. The change of normal visual acuity according to drifting angle of corrected axises of astigmatism, when we compared with full correction, appeared 0.94 in 5 degree, 0.87 in 10 degree, and 0.79 in 15 degree. Drift of 5 degree from fully corrected axis, corresponded to difference of visual acuity about one line, drift of 10 degree to 1.8 line difference of visual acuity, and drift of 15 degree about to 2.6 line difference. Through this study, we were sure that, in the case of drifting away from the right axis of astigmatism, it lead to visual weakness and asthenopia. Therefore we darely advise that optometrists should make mistake of axis least by confirming accucacy of corrected axis after despensing of spectacles of astigmatism.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.3
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• pp.205-213
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• 2005

To evaluate the reliability of binocular vision measurements by phorometry. 90 students volunteered to participate in this study. 25 subjects were males, and 65 were females, they ranged in ages from 21 to 30 years. All subjects had normal ocular and systematic health, and all of them had at least 1.0 visual acuity with their best correction. At negative relative convergence(NRC) measurement in distance, the percentage of subjects is included in expected value(blur point/break point/recovery point) was 78%/61%/67%, divergence excess(DE) was 9%/31%/33%, and divergence insufficience(DI) was 13%/8%/9%, respectively. And positive relative convergence(PRC) measurement, includes expected value was 20%/46%/39%, convergence excess(CE) was 22%/14%/16%, and convergence insufficience(CI) was 35%/40%/45%. AC/A ratios of 42 subjects were normal. 38 were low, and the rest of them high. A low AC/A ratio is usually the result of a small vergence response in relation to accommodation. Negative relative convergence(NRC) at near, includes expected value was 26%/29%/44%, divergence excess(DE) was 61%/33%/24%, and divergence insufficience(DI) was 3%/38%/32%. And PRC at near, includes expected value was 33%/40%/31%, convergence excess(CE) was 61%/23%/42%, and convergence insufficience(CI) was 6%/37%/27%. For the near point of convergence(NPC) test, 58% of their subjects had a break of ${\leq}8cm$ with the accommodative target. In case of NRA(PRA) measurement, the expected value was 41%(33%). Accommodative insufficiency (AI) was 33%(43%), and accommodative excess(AE) was 26%(24%), respectively. AE was related to respectively low values of NRA. AI and CE are associated with high value of NRA, and the dysfunction of convergence excess combined with AE was related to a normal-high values of NRA. PRA in AI was related to a low value, wheres the dysfunction are associated with high values of PRA.

• Journal of Broadcast Engineering
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• v.14 no.5
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• pp.638-649
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• 2009

Image resizing (or scaling) is one of the most essential issues for the success of visual service because image data has to be adapted to the variety of display features. For 2D imaging, the image scaling is generally accomplished by 2D image re-sampling (i.e., up-/down-sampling). However, when it comes to stereoscopic 3D images, 2D re-sampling methods are inadequate because additional consideration on the third dimension of depth is not incorporated. Practically, stereoscopic 3D image scaling is process with left/right images, not stereoscopic 3D image itself, because the left/right Images are only tangible data. In this paper, we analyze stereoscopic 3D image scaling from two aspects: geometrical deformation and frequency-domain aliasing. A number of 3D displays are available in the market and they have various screen dimensions. As we have more varieties of the displays, efficient stereoscopic 3D image scaling is becoming more emphasized. We present the recommendations for the 3D scaling from the geometric analysis and propose a disparity-adaptive filter for anti-aliasing which could occur during the image scaling process.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.19-27
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• 2004

The purpose of this study is to survey spectacle wearers's way of thinking through the questionaire and to investigate their wearing conditions through fitting conditions, the pantascopic angle, vertex distance, the coincidence of vertical and horizontal distance between optical center of the lens and pupillary distance of the eye in random selected 150 ametropic corrective wearers in the age of 17 to 19. The results are as follows : 1. The most popular causes of physical complaints in the ex-wearing spectacle are frame pressure(34.0%), slipping forward(30.0%) and most popular visual complaints are blur vision(30.0%) and asthenopia(20.0%). 2. The most common physical or visual complaints in the present wearing spectacle are slipping forward(30.0%), pressure (50.0%), color(10.0%). 3. Myopic glasses wearers accounted for 56.7% of the subjects, the others were compound myopic astigmatism. In 60% of the subjects' binocular diopter did not coincide. 4. In the pantascopic angle of the both eyes coincide in 66.7% of the subjects. The average of pantascopic angle is $10.07^{\circ}$. 5. In the vertex distance of the both eyes coincided in 65.3% of the subjects. the he average of vertex distance is 13.6 mm. 6. Among 150 eyes with monocular, the vertical distance between optical center of the lens and pupillary distance of the eye is within the RAL-RG 915 that is tolerance of ophthalmic dispensing in German Standards in 82 eyes (54.6%). 7. Among 150 eyes with monocular, the horizontal distance between optical center of the lens and pupillary distance of the eye is within the RAL-RG915 that is tolerance of ophthalmic dispensing in German Standards in 86 eyes(57.3 %).

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.369-375
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• 2015

Purpose: The current study was performed to estimate the changes in reading speed and blinking rate according to different background colors when reading paper book and further investigate their correlation. Methods: Twenty-nine adults (10 males, 19 females) who consented to the present study and had no ocular disease, ocular surgery history showing normal binocular vision were participated into the study. The subjects were asked to read the novels with black letter printed on white, red, green and blue background for 15 min, respectively. Then, the reading speed per page and blinking rate per page were measured during reading and analyzed according to background colors. Results: Reading speed per page according to the background color showed a tendency to accelerate in the white and green background as the reading time increased however, it was almost unchanged in the blue background and rather decelerated in the red background. On the other hand, the blinking rate per page tended to decrease in all background as the reading time was increased however, the smallest reduction was shown in the red background. There was a correlation that the reading speed increased as the blinking rate decreased in all backgrounds and the best correlation was shown in the green background. Conclusions: From the results, a correlation between the increasing reading speed and the reducing blinking rate while reading paper book with same demand on accommodation and convergence was confirmed however, the change in blinking rate and reading speed was varied depending on the main wavelength of light. It might mean that the working speed and visual fatigue can be varied depending on the difference of main wavelength when doing near work. Thus, it can be suggested that the adjustment of working environment and conditions should be made according to the kind of required perception.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.1
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• pp.53-61
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• 2005

In this study, we measured Near Point of Convergence(N.P.C) tests, Phoria tests using Von Grafe method and relative convergence tests on 138 men and 162 women, so a total of 300 subjects aged between 8~45 to examine the improvement of the fusion vergence through visual training and obtained as follows. 1. According to the results, the near point of convergence of 57 (19%) subjects were shorter than 7cm, and 243 (81%) were 7cm or longer, having a problem in convergence. After visual training, the number of subjects have the value shorter than 7 cm increased from 57 to 111 (37%), and the number of those have the value 7cm or longer decreased significantly form 243 to 189 (63%). 2. The results of the measure of lateral Phoria at far distance by Von Grafe method showed orthophoria 18 (6%), exophoria 198 (66%), esophoria 84 (28%). After phoria test, we examined the N.R.C and P.R.C test. The results showed that the hope finger was improved after V.T using B.l, B.O card. 3. The results of the measure of lateral Phoria at near distance by Von Grafe method showed orthophoria 6 (2%), exophoria 222 (74%), esophoria 72 (24%). After phoria test, we examine the N.R.C and P.R.C test. The results showed that the hope finger was improved after V.T using B.I, B.O card.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.117-124
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• 2015

Purpose: The purpose of this study was to compare the accommodative function of young adult in their 20s wearing monovision, modified monovision, and aspheric multifocal contact lenses at near task. Methods: Thirty young adults ($23.53{\pm}2.37years$) were fitted with monovision, modified monovision (the application of single vision contact lenses and center-near low addition aspheric multifocal contact lenses), and aspheric center-near multifocal contact lenses. After wearing these modalities during a week for adaption, and after watching visual display at computer for inducing accommodative pressure for 1 hour. The following assessments of accommodative function were made: contrast visual acuity (VA) at distance and near; accommodative response; near accommodative facility; and negative relative accommodation (NRA)/positive relative accommodation (PRA). All measurements were carried out binocularly. Results: In binocular distance VA with contrast of 10%, monovision was the worst among the four modalities (p=0.005). In accommodative response at 1 m (1.00 D), monovision was the lowest (p<0.05) and accommodative response at 40 cm (2.50 D) with monovision was lower than that of modified monovision and multifocal contact lens (p<0.05). We also found that there were no significant differences in accommodative facility and NRA/PRA among the four modalities. Conclusions: In young adult (20s), monovision with low add reduced the accommodative response at near task, however, modified monovision and multifocal lens with center-near type did not affect accommodative relaxation.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.363-368
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• 2015

Purpose: In this study, dominant eye is monitoring and level of dominant was measured in subjective and objective test. Methods: The average age of 21.08 years old of 129 adult (69 male, 60 female) who was no underlying ocular disease were participated in this study. dominant eye was determined by monocular instrument in subjecttive test and using a thin ring ($3.8cm{\times}3.8cm$) in objective test and level of dominant was measured direction of movement of the thin rim. Results: In the subjective test, there are 100 (77.52%) subjects whose dominant eye was right eye, and 29 (22.48%) subjects whose dominant eye was left eye. In the objective test, 90 (69.77%) subjects had right eye d and 33 (25.58%) subjects had left eye, as dominant eye, and 6 (4.65%) subjects had no dominant eye. Comparison of subjective test and objective test by dominant eye were equal in the 104 (80.62%) subjects, unequal in the 19 (14.73%) and center 6 (4.65%) subjects. The level of dominant eye in objective dominant eye test, there were middle 52 (57.78%) subjects, high 38 (42.22%) subjects in the right eye, and middle 25 (75.76%) subjects, high 8 (24.24%) subjects in the left eye. Conclusions: In this study O - Ring Test hasadvantage of direction and level of dominant eye, and middle or center dominant eye was shown in unequal. From this results, testing of dominant eye should be relationship equal and unequal, also required to be study in dominant eye level in binocular vision.