• Journal of Korean Ophthalmic Optics Society
• /
• v.17 no.4
• /
• pp.403-410
• /
• 2012

Purpose: The purposes of this study are to investigate accommodative response among emmetropes, spectacle wearer and contact lens wearer, and correlation between refractive error and accommodative respons for each group. Methods: The 72 subjects(144 eyes) who do not have any ocular diseases were participate in this study. Subjects were categorized into emmetropes, spectacle wearer and contact lens wearer by refractive error using closed-field auto-refractometer. We measured dominant eye, naked/habitual visual acuity and refractive error of monocular/binocular vision of refractive error for far/near distance with open-field auto-refractometer and calculated accommodative lag. Results: There were no significant difference of accommodative lag between right and left eye dominant and non-dominant eye, monocular and binocular vision, and spectacle lens wearer and contact lens wearer, However the accommodative lag of binocular vision was severe than monocular vision at near. The lag of myopia was larger than emmetropes, and male was larger than female. Significant correlation was found between refractive error and accommodative lag in total subjects and the same result was found in emmetropes and contact lens wearer. However there were no significant correlation in the spectacle wearer. Conclusions: There were significant difference between emmetrops and myopes in terms of accommodative lag, however accommodative lag of spectacle wearer was not different with contact lens wearer in myopes. There were also significant correlation between refractive error and accommodative lag in emmetropes and contact lens wearer, but the accommodative lag of spectacle wearer was not significantly correlated with refractive error.

• 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.20 no.3
• /
• pp.333-339
• /
• 2015

Purpose: The aim of this study was to evaluate clinical characteristics of subjective accommodative lags determined by fused cross-cylinder (subjective method), and an open-field autorefractor (objective method) under uncorrected and corrected conditions. Methods: Thirty three healthy subjects (26 males and 7 females aged $23.73{\pm}1.35$ years from 22 to 27 years) participated. Four methods were used to determine accommodative lag: (1) a subjective method with the fused cross-cylinder (FCC) under +2.00 D fogging lenses condition, (2) an objective method with the autorefractor under uncorrected condition (3) a corrected method (effective accommodative lag) using equations presented by Gwiazda et al. in objective methods, and (4) a corrected method using equations presented by Mutti et al. in objective methods. Results: The mean accommodative lags were 0.72 D for subjective method, 0.82 D for uncorrected objective method, 0.88 D for corrected method with Gwiazda's equations, and 0.78 D for corrected method with Mutti's equations. There were significant differences between the objective accommodative lags, but no significant differences between the objective and subjective accommodative lags. The effective accommodative lags showed significant correlations between phorias and refractive errors. The effective accommodative lag by Mutti's equations had a high correlation with uncorrected accommodative lags (r=0.99, p<0.001). Conclusions: The objective accommodative lag correlated with phorias and refractive errors. Especially, The effective accommodative lag using Mutti's equations may be considered for clinical availability and qualitative evaluation associated with symptoms.

• Journal of Korean Ophthalmic Optics Society
• /
• v.10 no.4
• /
• pp.381-389
• /
• 2005

To Analysis of Correlation of Visual Function Findings, by assessing convergence and accommodation, 92 selected objects without any ocular diseases by apperatuses of visual chart(Shinnippon CT30) and phoropter(Shinnippon VT10) at a shan distance(40 cm) were tested upon MEM retinoscopy(Welch Allyn, USA), BELL retinoscopy(Welch Allyn, USA), binocular accommodative facility (${\pm}2.00$ D nipper, Bernell Co., USA), vergence facility(prism nipper, Bernell Co., USA). The results showed as follows. MEM retinoscopy(accommodative lag) showed the same result of a right eye and left eye. Bell retinoscopy(accommodative lag) showed higher correlations between right and left eye than MEM. The lower accommodative lag meant the higher accommodative facility. The binocular accommodative facility(polaroid) was higher than binocular accommodative facility(red-green). Correlations of accommodative facility between right and left eye were higher, and as the higher monocular accommodative facility also meant the higher binocular accommodative facility, monocular and binocular accommodative facilities were relative to vergence facility, These findings can be used as a clinical guide by curing patients' visual function.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.2
• /
• pp.9-14
• /
• 2009

Purpose: The purpose of this study was to examine the relationship between the accommodative facility, blink rate and accommodative lag according to the change of angles of main viewpoint of near distance worker and study an appropriate viewing angle that mitigates asthenopia, such as headaches or eye fatigue accompanied when reading and staring at the computer or TV for a long time. Methods: Total of 27 people including 12 male university students and 15 female university students in the age of 20 to 36 with frequent near distance works, such as computers, were selected to study the accommodative facility, the blink rate and the accommodative lag in accordance with the change of viewing angles of the near distance workers. The refraction error was corrected completely and the phoropter was shifted to near distance mode to locate the near distance indication at 40 cm. The accommodative facility and the blink rate were measured for one minute at each viewing direction of $40^{\circ}$ downward, $20^{\circ}$ downward, horizontal, and $20^{\circ}$ upward directions based on the horizontal line and the accommodative lag was measured in dynamic retinoscopy using retinoscope. Results: As a result, when the main viewpoint was moved on upper direction from the $40^{\circ}$ below, the accommodative facility was reduced and the blink rate and the accommodative lag were increased so their eyes became dry and the accommodation response was reduced. Conclusions: In near distance works, the eye fatigue level can be minimized by locating a book or a computer screen $40^{\circ}$ below than the horizontal direction.

• The Korean Journal of Vision Science
• /
• v.20 no.4
• /
• pp.453-459
• /
• 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
• /
• v.19 no.2
• /
• pp.217-224
• /
• 2014

Purpose: This study was conducted to compare and analyze the accommodative system (accommodative response and accommodative lag) according to the material and font size of near visual media that we often encounter in daily life. Methods: Forty adult men and women aged 20 to 30 who not had specific ocular diseases and refractive surgery experience were examined to measure and compare the accommodative response according to the material of near visual media (print paper, newspaper, magazine, the I-Phone, LCD monitor) and font size (6, 8, 10, 12) by using both eyes open-view auto-refractometer. Results: The accommodative stimulus was $2.28{\pm}0.11D$ and the accommodative response was $1.66{\pm}0.30D$. The accommodative lag namely the difference between accommodative stimulus and accommodative response was $0.62{\pm}0.28D$. The accommodative response according to material of visual media using LCD monitor was $1.35{\pm}0.26D$ (p=0.00) and using the I-Phone was $1.55{\pm}0.25D$ (p=0.04). Both of them were statistically significant lower. The accommodative lag using LCD monitor was $0.93{\pm}0.24D$ (p=0.00) and using the I-Phone was $0.73{\pm}0.25D$ (p=0.04) and they were statistically significant higher. The accommodative response and accommodative lag according to font size were not statistically significant (p>0.05). Conclusions: During near working, the accommodative system was more affected by material than font size of visual media. Especially, visual media of non-luminous material (print paper, newspaper, magazine) are considered fewer burdens on eyes than luminous material (I-Phone, LCD monitor) in terms of accommodative system.

• Journal of Korean Ophthalmic Optics Society
• /
• v.17 no.3
• /
• pp.285-291
• /
• 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 Korean Ophthalmic Optics Society
• /
• v.17 no.2
• /
• pp.177-184
• /
• 2012

Purpose: In this study, the effect of the eye movement direction on visual function related to accommodation was investigated when playing computer games for a certain period of time. Methods: Total 60 subjects in 20s who had the visual acuity of 1.0 or higher without any ocular disease and accommodative dysfunction were asked to play computer games separately in horizontal and vertical directions for 40 and 90 minutes and then measured their accommodative amplitude, accommodative facility, accommodative lag and relative accommodations. Thevisual function when not doing the computer game was regarded as a control value, and further compared and analyzed. Results: The accommodative amplitude, accommodative facility, accommodative lag and relative accommodations showed the tendency of decrease after the computer game for 40 minutes, and more reduced values of the visual functions were shown when the computer game extended up to 90 minutes except positive relative accommodation. Positive relative accommodation had a tendency to increase slightly after the computer game for 90 minutes. Meanwhile, the change of the visual functions was primarily influenced by the eye movement in horizontal direction rather than by the eye movement in vertical direction during computer game when analyzed by the direction of eye movement. Conclusions: Over all accommodative functions tended to decrease with the extended VDT working time by computer game, and the frequent eye movement in horizontal direction during VDT tasks could be the main cause of eyestrain since the eye movement in horizontal direction rather than vertical direction significantly affected the change of accommodative function.

• Journal of Korean Ophthalmic Optics Society
• /
• v.19 no.2
• /
• pp.253-260
• /
• 2014

Purpose: The present study was conducted to investigate whether near work with smartphone could induce the change of accommodative function. Methods: Total 63 subjects(26 male and 37 female) in their 20s were firstly examined their visual functions related to accommodation and uncorrected spherical equivalent power as the control. After that, the subjects were asked to read a book for 30 min and sequentially watch a movie on smartphone for the same time after 30 min-break under the indoor light or as it was in the reverse order to avoid time-ordered effect. Their accommodative functions, 1) accommodative amplitude, 2) accommodative facility, 3) relative positive/negative accommodation, and 4) accommodative lag and their uncorrected spherical equivalent power were examined again following each task and compared with the control values. Results: The monocular accommodative amplitude was significantly decreased after smartphone watching compared with it after reading. The monocular and binocular accommodative facilities were tended to reduce after smartphone watching and book reading but were not significantly different. Neither significant change in positive relative accommodation was determined after smartphone watching nor book reading. Negative relative accommodation after smartphone watching was almost unchanged unlike reading a book. The accommodative lag after smartphone work was significantly higher than after book reading. Conclusions: The near work with a smartphone for 30 min induced the change of some accommodative functions, which was significantly greater than when reading under the same working environment.