• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1747-1754
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• 2013

We evaluate the impact of near work has on myopia and how they differ across generation. The study subjects were 201(83 males and 118 females) adults who live in Cheongju and Daejeon. Myopia was defined as more than or equal to (-)2.50D. The subjects were divided myopic and control group. The surveys and eye tests that are related to near work and refractive error were conducted and the relationship between the degree of myopia and near work was investigated. Then, the groups were divided into people in their 20s and 30s and the comparisons were made again. The survey results showed significant differences between myopic and control groups that depended on: hours spent in school and outdoor activities during high school period, degree of refractive error caused by level of exercises during the junior high school and high school years, refractive error based on the type of high schools, also hours spent in school and outdoor activities. When the same question was done on the group in their 20s and 30s, there was a different outcome in trends between the groups and refractive error depending on whether they exercised. The degree of near work is one of the environmental risk factors that affect myopia and must be considered when studying myopic progression. However, when discussing specific behavioral patterns in relations to myopia prevention, culture and visual environment of a given generation must also be considered.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.531-536
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• 2018

The purpose of this study is to investigate eye fatigue and analyze symptoms of visual discomfort according to near work in young adults. A survey was conducted on 347 young adults aged 25.37 years (142 male and 205 female participants). The eye fatigue using Conlon questionnaire were surveyed and near work was investigated amounts of daily computer and smartphone. The score of eye fatigue was $13.65{\pm}7.11$ in less than 2 h/d, $16.83{\pm}6.77$ in 2~4 h/d, $18.88{\pm}6.60$ in 4~6 h/d, and $18.83{\pm}5.62$ in more than 6 hours(p=0.001). Also, headache(p<0.030), re-reading(p<0.036), and movement and fading(p<0.001) symptoms increased according to amounts of near work.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.397-402
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• 2014

Purpose: To investigate the relationship between axial length (AL) and anthropometric parameters in Korean children. Methods: This study included 40 urban school children aged 11-12 years (mean age, $11.95{\pm}0.22$ years; 45.0% girls) residing in Seoul, South Korea. AL (using partial coherence laser interferometry), corneal radius, refractive error, height (m), and weight (kg) were measured. Body mass index (BMI $[kg/m^2]=weight/[height]^2$) and degree of obesity (DO[%]=[actual weight standard weight]/standard weight) were calculated. Furthermore, the number of hours spent reading, watching television, and using a computer every day was determined using a detailed questionnaire. Results: The students had a mean spherical equivalent refraction of $1.06{\pm}0.84$ D. Weight (r=0.427, p=0.006), BMI (r=0.508, p=0.001), and DO (r=0.371, p=0.018) showed a significant positive correlation with AL. Furthermore, longer AL was significantly associated with heavier weight (p=0.041), and higher BMI (p=0.015), and higher DO quartiles (p=0.042). After adjust for age, sex, and near-work activities, multivariate linear regression models showed that weight, BMI, and DO were still significantly associated with AL. Among the near-work activities, daily reading time was significantly associated with AL. Conclusions: AL was positively related to weight as well as daily reading time in Korean urban school children.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.395-401
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• 2012

Purpose: The purpose of this study was to research any effect on vision protecting or decreasing VDT syndrome of extracted anthocyanine from fermented purple sweet potato and blueberry. Methods: Subjects were aged 19-20 years old who do not have ophthalmic and systemic diseases and over -N4.00 D of refraction error. 40 mg of extracted anthocyanine from fermented purple sweet potato, from blueberry, and control group, placebo were dosed at separate try. After 2 hours later, subjects were directed perform visual display terminal (VDT) work for 2 hours. Objective refractive error was measured before dosing anthocyanine and after VDT work for 2 hours. Degree of head ache, eye pain and strain and subjective symptoms of neck, shoulder and waist was also examined through interviews by dividing its degree into severe, moderate, slight or none. Results: After 2 hours VDT work, vision protection effect in terms of refractive error for dominant eye was decreased by $0.031{\pm}0.21$ D in the group of extracted anthocyanine from fermented purple sweet potato, $0.006{\pm}0.32$ D in the group of extracted anthocyanine from blueberry. However, there was significantly myopic progression in the placebo group by $0.144{\pm}0.28$ D (t=2.27, p=0.03). Conclusions: It is considered that extracted anthocyanine from fermented purple sweet potato inhibits increase of refraction anomalies of dominant eye rather than non-dominant eye after VDT work.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.125-130
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• 2007

The aim of this work was to study the relationship between subjective symptoms and binocular function during near work in forty one(12-17yr) schoolchildren. CISS symptom survey, amplitude of accommodation, accommodative facility, neagative relative accommodation(NRA)/positive relative accommodation(PRA) near point of convergence(NPC), heterophoria, AC/A ratios were measured. The results of measurement were compared with normal expected value of each test and classified into normal and abnormal group. Accommodative insufficiency was more general than convergence insufficiency and esophoria was greater than exophoria. NRA/PRA showed very high and AC/A ratios were very low compare with normal expected value. The results of CISS was as follows; most frequent symptom was tired, mean score was $16.63{\pm}7.49$, mean number of symptoms were $10.07{\pm}3.04$, and mean number of serious symptoms were $1.98{\pm}2.13$. After classified into 4 groups according to score of symptoms, number of symptoms, and degree of symptoms and then analyze the correlation compare with binocular vision test results. NRA was most correlated with group comparison, accommodative facility was most correlated with score of symptoms, NRA was most correlated with number of symptoms, and near horizontal phorias were most correlated with serious symptoms. NRA showed most correlative relation with near symptoms.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.75-81
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• 2011

Purpose: The daily changes of accommodation at period 1 (08:00~10:00), period 2 (13:00~15:00) and period 3 (18:00~20:00) were surveyed with fifty two incipient presbyopia of from 38 to 49 years old. Methods: 52 incipient presbyopia subjects (30 men, 22 women) were classified into 4 groups (groupI: ${\geq}$ 7 hrs~group IV: < 3 hrs) according to near working amount. Their amplitude of accommodation, accommodative facility and relative amplitude of accommodation were inspected, respectively. Results: The amplitude of accommodation was measured to be the lowest for the groupI that near working time was the most during daily work, and the amplitude of accommodation of oculus dexter, oculus sinister and oculus uterque were the highest at period 2 in case of all the group I~IV. In the accommodative facility, it appeared that the oculus dexter, oculus sinister and oculus uterque of group I, oculus dexter and oculus sinister of group II, and oculus dexter, oculus sinister and oculus uterque of group III were the highest at period 2. The oculus uterque of group II and oculus dexter, oculus sinister and oculus uterque of group IV were the highest accommodative facility at period 3. It appeared that the negative relative accommodation was the highest at period 1 in case of all the group I~IV, and the positive relative accommodation was the highest at period 2 in case of the group I~III and was the highest at period 3 in case of the group IV. Conclusions: Because the difference of near working time affects the accommodation, it would become a help in solving the asthenopia symptom of the incipient presbyopia that opticians consider their near working time during daily work and take a checkup on their accommodation.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.219-228
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• 2015

Purpose: The current study was performed to compare the difference in binocular visual function depending on variable background colors at near work. Method: Fifty four adults (18 males, 34 females) who consented to the present study and had no ocular disease, ocular surgery history, strabismus and amblyopia with normal binocular vision were participated into this study. The subjects were asked to read the novels with black letter printed on white, red, green and blue background for 15 min. Then, their heterophoria, AC/A ratio, near point of convergence, accommodation facility, relative accommodation and vergence were measured before and after reading. The difference of measurements were compared. Result: Overall heterophoria was tended to decrease with regardless of background color. AC/A ratio showed a tendency of increase after reading the novels with all backgrounds except white background. Near point of convergence was significantly increased compared to before reading at all background color. Accommodative facility of dominant and non-dominant eyes were also significantly increased after reading however, binocular accommodative facility showed a tendency of decrease. Negative relative accommodation also decreased at all background colors however, the change of positive relative accommodation was not significantly different. In case of vergence, there was significant difference in break point of far BO and recovery point of far BI by the wavelength of background color. Conclusions: From the results, it was known there is convergence change depending on the wavelength of light even though same amount of accommodation and convergence is required when doing near work for certain period. Thus, it can be suggested that the adjustment of the near working environment which perception of various color was required, should be conducted according to the main wavelength.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.255-261
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• 2015

Purpose: purchasing status and understanding trends of Functional progressive addtions lenses buyers', Correlation analysis of the Binocular Function value to determine ADD then can be apply sales and prescriptions. Methods: Years 2011 to 2014, 298 patients who were prescribed functional progressive lenses were analysed based on the prescription data and SPSS (Ver. 20.0) was treated using the statistics. Results: Results: The average age of our customers are $27.66{\pm}11.55$ years, average addition power is $+0.73{\pm}0.36D$, customers are using take a prescription of ADD $+0.75{\pm}0.28D$ was the highest 44.33% to 132 people. Near point of convergence of 276 people (92.62%) was mostly less than 10 cm, and near point of accommodation of 134 people (44.97%) was also below 10 cm, within 11~15 cm were 122 people (40.94%). Most of people were within normal range in terms of Near point of convergence and near point of accommodation, near point of accommodation tend to be longer than Near point of convergence. As you can see this result shows most of customers need extra help in their near point of accommodation instead of they are leak at it. FCC (Fused cross cylinder) check Value and ADD (addition power) tests showed that the value of a strong correlation (p=0.00), NPC and NPA were also p=0.001, the correlation of the NPC and ADD is p=0.003, In addition, NPA and ADD also showed a significant correlations (p=0.005). Near Point of Accommodation, negative relative accommodation, and positive relative accommodation are all significantly correlated (p=0.00). The short distance-related variables of the ADD which are NPC, NPA, Age, also appeared to side correlate significantly with each other. Conclusion: Binocular function values of the subjects were highly correlated with each other so precise examination is required. when Age young people are working at short distance, low ADD values was prescribed for solving discomfort. So, in the case of early presbyopia, accommodative insufficiency, or people feel fatigue when they often working at near although their accommodation function is normal, when functional progressive lenses are prescribed, expectation of this should be exactly notified.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.73-78
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• 2010

Purpose: The purpose of this study was to examine diurnal variation of accommodation on people whose age are between 35 and 50 years old with frequent alternation of accommodation at period 1 (8:00-10:00), period 2(13:00-15:00) and period 3 (18:00-20:00). Methods: All \04 subjects were separated to nonpresbyopia and incipient presbyopia. Tests were done for amplitude of accommodation, accommodative facility and relative amplitude of accommodation. Results: Both nonpresbyopia and incipient presbyopia had the highest amplitude of accommodation in oculus dexter, oculus sinister and oculus uterque at period 2. In addition, the incipient presbyopia showed the statistical significance of daily change. The nonpresbyopia had the most accommodative facility at period 3 and incipient presbyopia had the most accommodative facility at period 2. Their daily variations were statistically significant. Both nonpresbyopia and incipient presbyopia had the most negative relative accommodation of daily change at period I. Both of them had the most positive relative accommodation at period 2. Conclusions: The incipient presbyopia had the highest amplitude of accommodation, accommodative facility. and positive relative accommodation (except the negative relative accommodation) at period 2.

• 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.