• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.2
• /
• pp.137-142
• /
• 2013

Purpose: This study was designed to investigate the current status of visual acuity for elementary school students in Muan-gun and to analyze improvements of their visual function after vision training for the elementary school students who have either insufficiency of accommodation or vergence. Methods: Subjective refraction, objective refraction and binocular function were examined for 335 elementary school children from year 1 to year 6 live in Muan area, and then 47 students who have symptoms of binocular dysfunction among them were selected. We analyzed and compared between before and after vision training (VT) in binocular vision function results. Results: The results show that most of the subjects had much problem in near point convergence (NPC) than accommodation. After the vision training, the average of subjects NPC was improved about 5.93 cm, from $11.57 {\pm}1.850$ cm for before VT to $5.66{\pm}0.965$ cm for after VT. After VT positive fusional vergence at near distance after VT was $19.64{\pm}3.66$ $\Delta$, which was as much as double of near phoria. Accommodative amplitude was improved from $10.02{\pm}2.566$ D for before VT to $12.30{\pm}1.397$ D for after VT, which similar to mean of expected accommodative amplitude of 11.27 years old. Conclusions: Among insufficiency of accommodation and vergence NPC was improved specially, and accommodative facility and other ocular functions were also improved. Therefore, it is considered the vision training is very effective to recover from visual function problems.

• Journal of Korean Ophthalmic Optics Society
• /
• v.17 no.2
• /
• pp.159-164
• /
• 2012

Purpose: Of the various methods of vision training, the essay aims to explore the effective ways of using the Fresnel prism lens in order to expand the positive fusional vergence for the patient having specific condition of convergence insufficiency or basic exophoria. Methods: 15 students of city of Daejeon university without an eye disease (average age $22.73{\pm}1.68$) were selected and underwent the subjective refraction test and binocular vision test, and recording their test results before vision training and replacing an identical frame with a lens of same quality after the full calibration, the lens was then adhered with the Fresnel prism lens and continued to train for thirty minutes daily during two weeks. Afterwards, the binocular vision test was reattempted. The observation of the change in the results of the binocular vision test in use of the fresnel prism lens in the vision training test was researched. Results: After training, the positive fusional vergence had increased to a number of $22.27{\pm}2.26$ $\Delta$, to 7.80 $\Delta$, at near, the fused cross cylinder test increased to an average of $0.55{\pm}0.09$ D, 0.40 D after training, showing a normal result. The value of negative relative accommodation after training had an average of $2.22{\pm}0.08$D, showing that 0.42 D had increased. The value of near point of convergence after training had an average of $6.13{\pm}0.53$ cm, showing that 2.80 cm had decreased. To patients who had convergence insufficiency or basic exophoria, the value of the near vision test that used the Fresnel prism lens which was able to expand BO positive fusional vergence had increased without phoria. Conclusions: The changes were tested and the effectiveness of the Fresnel prism lens, due to the nature of the lens itself, helped with both cosmetic effects and cost. It also allows good optical correction effects, in addition to these clinical effects indicated before. Therefore, it may be determined that the Fresnel prism lens binocular vision therapy for patients is more popular and highly recommended.

• Journal of Korean Ophthalmic Optics Society
• /
• v.9 no.2
• /
• pp.223-231
• /
• 2004

In most previous studies, the assessment of accommodative convergence to accommodative stimulus (AC/A) ratio was commonly made by measuring gradient AC/A ratio. This study deals with the proximal convergence/accommodation(PC/A)ratio measured by comparing values of the gradient AC/A ratio and the calculated AC/A ratio to prevail the clinical use of the AC/A ratio. Visual acuities of All 124 subjects had been corrected to at least 1.0 with either eye through their habitual refractive correction and the MEM dynamic retinoscopy was performed to estimate their accommodative response. And then the PC/A ratio was calculated by making use of the calculated AC/A ratio and the gradient AC/A ratio. This study showed that the difference between the mean calculated AC/A ratio and the mean gradient AC/A ratio in subgroups may be attributable to proximal convergence. Consequently, further studies on proximity cues including the PC/A ratio could be helpful to prevail the clinical use of the AC/A ratio.

• Journal of Korean Ophthalmic Optics Society
• /
• v.10 no.4
• /
• pp.419-428
• /
• 2005

The aim of this study was to provide data for the relief of asthenopia during binocular vision by determining the characteristics of ocular function in adults. A total of 260 subjects were between the age of 19-35years. We measured individually the refractive error correction, pupillary distance, optical center distance, phoria, convergence, accommodation and the AC/A as well as the asthenopia during binocular vision using a questionnaire. After analysis of factors affecting asthenopia, we also examined the reductive effect of asthenopia in subjects who had asthenopia using prism. To determine the factors affecting asthenopia during binocular vision, statistic analyses were carried out the multivariate Logistic regression model. The results of this study were as follow. The asthenopia during binocular vision was found 26.9% of subjects. Multivariate logistic regression model was used to determine factors affecting binocular vision of myopia. When the accommodation and convergence were low compared to being high, when subjects had esophoria or there was more exophoria, and when AC/A was lower than the standard, the rate of asthenopia was higher. Therefore the accommodation, convergence and AC/A could be predictive factors for asthenopia. We used prism for subjects who had asthenopia during binocular vision, the results showed that the symptom of asthenopia was eased up to 74.3%.

• Journal of Korean Ophthalmic Optics Society
• /
• v.21 no.2
• /
• pp.127-135
• /
• 2016

Purpose: The present study was aimed to investigate the effect of excessive near work by using a smartphone on subjective symptoms and accommodative and convergent function in their 40s. Methods: A total of 40 subjects(male, 10; female, 30; age, $43{\pm}7.2year$) in their 40s who have monocular and binocular visual acuities of 0.8 and 1.0, respectively, were divided into presbyopia group and non-presbyopia group. The subjects were asked to watch a movie on the screen of smartphone for 30 minutes. Their accommodative amplitude and facility, and relative accommodation were measured and compared before and after the use of smartphone. Changes in fusional vergence and near heterophoria by using smartphone were also evaluated. Furthermore, the change of subjective symptoms was surveyed using a questionnaire. Results: The presbyopia in mid-40s reported discomfort in an order of asthenopia, blur and dryness after the use of smartphone. Accommodative function and non-strabismic binocular function were generally decreased. Accommodative functions such as monocular accommodative amplitude, and relative accommodation were significantly decreased after smartphone use, and the change of phoria was observed as a result of decreased convergence and divergence. Negative fusional vergence was also significantly reduced. On the other hand, non-presbyopia in mid-40s reported discomfort in an order of asthenopia, dryness and blur, and only accommodative amplitude among the accommodative functions was significantly reduced. Significant reduction of negative fusional vergence was also observed. Conclusion: From the results, it was confirmed that the subjective discomfort of mid-40s after smarphone use might be related to whether presbyopia or not. It was due to not only the reduction of accommodative function but also the overall deterioration of visual function including heterophoria and fusional vergence. Therefore, it suggests that the accurate determination of the cause based on the overall visual functional tests such as heterophoria, fusional vergence as well as the decrease of accommodation due to the aging may be necessary when the mid-40s feels discomfortable symptoms by near work.

• Journal of Korean Ophthalmic Optics Society
• /
• v.10 no.3
• /
• pp.205-213
• /
• 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 Korean Ophthalmic Optics Society
• /
• v.20 no.3
• /
• pp.363-368
• /
• 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.

• Journal of Korean Ophthalmic Optics Society
• /
• v.21 no.3
• /
• pp.227-233
• /
• 2016

Purpose: On this study, we compared the relationship of dynamic stereoacuity according to the dominant eye, degree of dominant eye, and dominant agreement eye and hand. Methods: For 130 adults (male 70, female 60), mean age of $21.06{\pm}2.21years$ old, dominant eye, degree of dominant eye were measured by objective examination by using the diameter $3.8cm{\times}3.8cm$ thin ring, the dynamic stereoacuity were measured by three-rods test (iNT, Korea). Results: Dynamic stereoacuity according to the dominant eye was center dominant eye without dominance was $14.97{\pm}13.80sec$ of arc, right eye $22.10{\pm}20.01sec$ of arc, left eye $22.31{\pm}20.39sec$ of arc. Dynamic stereoacuity was better when there was no dominance, but the correlation of the dominant eye with dynamic stereoacuity was very low. When Dynamic stereoacuity was separated by in the Center, Mild, Strong, dynamic stereoacuity was $14.97{\pm}13.80sec$ of arc, $20.76{\pm}15.73sec$ of arc and $24.45{\pm}25.60sec$ of arc respectively. The dynamic stereoacuity results were worse when dominance was stonger. However dynamic stereoacuity was better than Center when the degree of dominant eye was rather strong in the dominant left eye. Dynamic stereoacuity according to the dominant eye and hand showed that right eye and hand was $22.63{\pm}20.54sec$ of arc, left eye and hand was $17.36{\pm}10.13sec$ of arc, right eye and left hand was $14.79{\pm}7.05sec$ of arc, left eye and right hand was $22.97{\pm}21.42sec$ of arc so dynamic stereoacuity was comparatively good when the dominant hand was left. Conculsions: Correlation between the dynamic stereoacuity according to the dominant eye, degree of dominant eye was low, however when degree of dominant eye was Center 14.97 sec of arc, Strong 24.45 sec of arc, the dynamic stereoacuity tended to worse when degree of dominant eye was strong. As a result, dominant eye, degree of dominant eye would have to be considered in a more comfortable binocular balance between prescribed for the wearer in binocular vision correction in binocular function such stereoacuity, sports vision training, presbyopia correction and mono vision.

• Journal of Korean Ophthalmic Optics Society
• /
• v.17 no.1
• /
• pp.59-65
• /
• 2012

Purpose: The purpose of this study was to determine the distribution and correlation of accommodative lag with refractive error. Method: We had tested the clinical refraction and the accommodative lag in clinically normal 49 young adults (total 98 eyes) aged 18 to 25 years without abnormal binocular function. Monocular and binocular accommodative lag were tested with 0.50 D cross-cylinder lens and near vision test chart which had cross-hairs after full correction of LogMAR visual acuity over 0.05. Results: There was no statistical differences in monocular accommodative lag between right ($0.64{\pm}0.64$ D) and left eye ($0.63{\pm}0.64$)(p=0.858). The accommodative lag of male was higher than female and the range of the value was broader than female in binocular accommodative lag (p=0.015). The wider the inter-pupillary distance was, the higher the accommodative lag was (p=0.003). However, there were no differences with age (p=0.800) and dominant eye (p=0.402). The ranges of accommodative lag of low, middle, and high myopia were 0.75 ~ -0.25 D, 1.25 ~ -0.50 D, and 1.50 ~ -0.75 D, respectively, and the regression was 'y = -0.03953x+0.09205'. Conclusions: These data suggest that clinically normal young adults with high amounts of refractive error have more variable accommodative lag and increased spherical equivalent refraction.

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