• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.273-278
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• 2012

Purpose: Average of the maximum accommodation amplitude of myopia in different generation, early 20's and early 40's were compared according to gender, degree of myopia. Methods: Maximum amplitude of accommodation for each 100 patients of early 20's and 40's were measured with push-up method. Maximum amplitude of accommodation expectations based on Hofstetter formula were classified into three groups of under, normal and excess. Results: The average of amplitude of accommodation was 9.77~11.64 D $(10.77{\pm}2.49D)$ in early 20's and 4.67~6.21 D $(5.34{\pm}1.28D)$ in early 40's. In early 20's, minimum expectations of amplitude of accommodation for under, normal and excess groups were 20%, 75%, and 5%, repectively. In early 40's, excess and under groups were 5% and 18%, repectively, but there was no excess group. Conclusions: According to increasing age, amplitude of accommodation of both age groups showed decreased, and no significant difference was found in degree of myopia with gender. Difference between mean of expected accommodation amplitude and maximum of accommodation amplitude was compared, and it was found that maximum of accommodation amplitude of 20's was smaller than mean of expected accommodation. From the result, it was expected that people in early 20's who have more working times might have festinated accommodative insufficiency than 40's.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.107-110
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• 2007

Analysis of accommodation amplitude has been conducted for 137 adults, living in rural area, aged from their fifties to eighties. The methods included measurement of correction power for distance via auto-refractometer, measurement of near power based on trial frame and trial lens set, and calculation of effective accommodation amplitude using 1/2 and 2/3 of the maximum accommodation amplitude. The research results for participants aged in their fifties, sixties, seventies, and eighties showed 1.84~2.46D, 1.55~2.06D, 1.43~1.90D, and 1.22~1.62D respectively. It is relatively higher than the existing knowledge regarding accommodation amplitude associated with age.

• 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.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.5
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• pp.417-425
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• 2000

The underlying mechanism commonly applicable for both the positive and negative force-frequency relationships (FFR) was pursued in left atria (LA) of rat and rabbit. The species differences in the roles of $Na^+/Ca^{2+}$ exchanger and sarcoplasmic reticulum (SR), which are major intracellular $Ca^{2+}$ regulatory mechanisms in the heart, were examined in the amplitude accommodation to the frequency that changed from 3 Hz to the variable test frequencies for 5 minutes in the electrically field stimulated left atria (LA) of rat and rabbit. Norepinephrine strongly increased the frequency-related amplitude accommodation in both of rat and rabbit LA, while monensin, oubain or the reduced $Na^+$ and 0 mM $Ca^{2+}$ containing Tyrode solution increased the frequency-related amplitude accommodation only in the rabbit LA. Monenisn was also able to increase the frequency-related amplitude accommodation only in 1-day old rat LA but not in 4-week old rat LA that had 75% less $Na^+/Ca^{2+}$ exchanger with 97% higher SR than 1-day old rat LA. Taken together, it is concluded that the differences in the prevalence between myocardial $Na^+/Ca^{2+}$ exchanger and SR in the amplitude accommodation to the frequency-change determine the difference in the FFR between rat and rabbit heart.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.453-459
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• 2018

Purpose : This study was to investigate the change of accommodative functions by different color density and color of colored lenses. Methods : Participant had a normal NPC and no dyschromatopsia, phoria and eye disease, also had no histories of eye surgery in 31 students of university. Their accommodative functions were measured according to 50%, 80% density of the gray, blue, brown lens and non-colored lenses. Tests of accommodative functions performed include amplitude of accommodation, accommodative facility, relative accommodation, and accommodative lag. Results : The amplitude of accommodation and accommodation lag were increased when wearing the colored lens. Negative relative accommodation was more increased when wearing the colored lens than achromatic. Positive relative accommodation increased when wearing the blue color lens density by 50%. Also, accommodation facility increased when wearing the colored lens, but, as the density of the color increased, the accommodation facility was decreased. Conclusion : As since the accommodation function changes according to density of the colored lenses, working distance and environment of the wearing colored lens should be considered when selecting density and color of colored lenses.

• 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.3 no.1
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• pp.75-86
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• 1998

The purpose of this study is to evaluate the effects of continuing work on VDT(video display terminal), therefore this study examined visual fatigue, unaided visual acuity, refractive error, accommodation and horizontal phoria of 152 subjects who did two hour long VDT work. For the ocular symptoms, the greatest number was tired eyes accounting for 45.71%. In the visual symptoms, blurred vision was the hightest rate of 80.39% and in case of systemic symptoms shoulder pain was 33.33% marked top ranking. The average of near visual acuity decresed almost 10% from 0.47 to 0.42, but refractive error increased about 0.10D to the direction of myopic shift. The amplitude of accommodation decreased approximately 0.72D from 7.46D to 6.74D. Accommodation facility was delayed from 2.27 second to 2.50 second, the amplitude of positive relative accommodation was decreased from 4.76D to 4.16D and the amplitude of negative relative accommodation was decreased from 2.46D to 2.33D. The horizontal phoria shifted to the direction of esophoria from $1.82{\Delta}$ to $3.24{\Delta}$.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.285-291
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• 2012

Purpose: This study was conducted to research any effect on visual function related to accommodation by VDT work. Methods: The refraction power, accommodative lag, accommodative facility, relative accommodation, amplitude of accommodation and blink rate were measured before and after VDT work for 2 hours on 48 university students (16 males and 32 females), without abnormal accommodative function and systemic and ocular disease, who had never undergone corrective eye surgery. All examinations were performed with distant refraction, and a survey was conducted on the items related to subjective symptoms of VDT syndrome. Results: After 2 hours of VDT work, refractive power increased by 0.23 D, the amount of change in accommodative lag were $0.17{\pm}0.42D$ in the right eye and $0.23{\pm}0.47D$ in the left eye (t=2.26, p=0.03). There were statistically significant differences. Both the accommodative facility and relative accommodation and amplitude of accommodation were decreased after work. However, blink rate were increased. After VDT work, 33.4% of the subjects showed subjective symptoms of asthenopia and 33.3% of them showed shoulder pain. Conclusions: As a result, the accommodative lag increased in response to the two hours of VDT work, and overall accommodative functions were decreased. In addition, as symptoms of providing visual strain, asthenopia showed the most prominent subjective symptoms.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.599-608
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• 1997

We studied on change of lens accommodation and pupil light reflex caused by VDT work in six women and compared them with those of other office works. The results were as follows. 1. In VDT work the accommodation contraction velocity decreased during the first 2-hr VDT task, then recovered markedly by the end of the one-hour lunch break, and decreased again by the end of the 2nd 2-hr VDT task. Changes of relaxation velocity showed similar pattern although it was less typical than that of contraction velocity 2. There was no marked change in accommodation contraction velocity and amplitude of accommodation in general office work and near-distance office work, and in the near-distance office work accommodation relaxation velocity decreased according to work load without recovery after lunch break. 3. Initial pupil diameter, initial pupil area of light reflex decreased significantly during VDT task only in VDT work and didn't recover after lunch break. These results suggest possibility that changes of accommodation contraction velocity, accommodation relaxation velocity, near point distance, and pupil diameter and area are useful in evaluating characteristics of VDT work. For this, more research adjusted individual differences, circadian rhythm, emotional stress needs.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.195-200
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• 2015

Purpose: This study was performed in order to figure out the influence of illumination on visual function. Methods: 40 adults (male 21, female 19) of average age $23.93{\pm}1.59$ years were participated in this study. The test chart surface illumination was adjusted to 5, 50, 200, 500 and 800 lx, and then amplitude of accommodation, near point of convergence, far and near distance phoria, far and near distance fusional vergence, relative accommodation, and accommodation lag were measured at each illumination condition. Results: As illumination intensity of test chart was reduced, amplitude of accommodation was significantly decreased (p<0.05), accommodation lag was also decreased, near point of convergence was receded, and horizontal phoria showed a tendency of esodeviation. In the case of negative fusional vergence, with reduction of illumination intensity, the break point and the recovery point were decreased but in the case of positive fusional vergence, the break point was increased. The negative and positive relative accommodation were significantly decreased (p<0.05) with reduction of illumination intensity. Conclusions: In clinical practice, visual functional test should be performed under condition of adequate illumination level through patient's living environment and job.