Earticle

본 연구는 근시성 난시안에서 난시축의 변화에 따른 시력상태를 비교분석하고, 정확한 시력검사와 처방서에 따른 난시 교정용 안경의 조제 가공 오차를 최소화 하고자 한다. 안질환 및 전신질환이 없는 근시성 난시를 가지고 있는 남·녀 93명(186안)을 대상자로 선정하였다. 완전교정상태에서 난시축의 5°, 10°, 15° 변화하였을 때의 시력을 비교하였다. 난시의 종류는 186안 중에서 중에서 직난시의 비율이 가장 높았다. 1.0으로 완전교정시 난시축의 변화에 따른 시력의 변화는 난시축 변화가 크면 클수록 시력이 감소하는 것으로 나타났다. 난시의 형태는 연령의 증가와 함께 직난시에서 도난시로 바뀌는 것을 알 수 있었으며, 난시의 교정축 변화가 클수록 교정시력은 떨어지는 것으로 나타났다. 난시의 굴절검사를 실시할 때는 난시도수와 난시축을 정확히 검사하고 교정하는 것이 융합되어야 할 것이다.

The purpose of this study is to compare the status of eyesight according to the change of astigmatism axis in myopic astigmatism and to minimize errors in making astigmatic glasses based on accurate optometry and prescription. The subjects were 93 males and females(186 eyes) who have myopic astigmatism without any ocular disease or systemic disease. We performed comparative analysis on the status of visual acuity according to the change of astigmatism axis to 5, 10 and 15 degree in corrected eyesight 1.0. The direct astigmatism was the most common astigmatism type among the 186 eyes. After all subjects were perfectly corrected into 1.0, the change of astigmatism axis affected eyesight; The results suggested that the more change was made in astigmatism axis, the worse their eyesight would become. The main astigmatism type was changed from direct astigmatism to inverse astigmatism as age increased. The change of the astigmatism axis resulted in failing of corrected eyesight. Therefore, the convergence of examination and correction for astigmatism strength and axis is necessary when conducting refraction inspection for astigmatism.

Objective: In general, macular degeneration, cataracts and glaucoma generally cause visual injury in clinical settings. This study aimed to examine the effects of low visual acuity simulations on hand manual dexterity function and brainwaves in healthy young adults. Design: Cross-sectional study design Methods: This study was an observational, cross-sectional study. Seventy healthy young adults participated in this study. To evaluate the effects of low visual acuity simulations on hand function and brain waves, this study involved four different visual conditions including (1) normal vision, (2) simulated cataracts, (3) simulated glaucoma, and (4) simulated macular degeneration. The hand function was measured to use the Minnesota manual dexterity test (MMDT), and the brainwaves was also measured to use the electroencephalography. Results: In hand function, placing and turning performance on the MMDT in the normal visual condition was significantly different than that in the cataract and macular degeneration conditions (p<0.05), and the placing performance was significantly differred in the normal condition than that in the simulated glaucoma. However, turning was not significantly different in the normal condition than that in the simulated glaucoma. The alpha, beta, and gamma waves did not significantly differ among the four visual conditions (p>0.05). Conclusions: The results suggest that limited visual information negatively affects the ability to perform tasks requiring arm-hand dexterity and eye-hand coordination. However, the effectiveness of low visual acuity on the brainwaves should be further studied for rehabilitative evidence of visual impairment.

미취학아동의 시력검진실태와 시력저하 관련요인을 확인하기 위해 2015년 8월부터 2016년 1월까지 어린이집 및 유치원에 다니는 5세~7세의 아동 172명과 그 부모 중 1인 172명을 대상으로, 보호자에게는 설문조사를, 아동에게는 시력측정을 실시하였다. 시력검진 실태는 평균, 표준편차, 백분율 등 서술적 방법으로 분석하였고, 시력저하 관련요인은 로지스틱 회귀분석으로 확인하였다. 전체 아동 172명 중 128명 (74.4%)이 시력검진 경험이 있었으며, 77명(44.8%)이 시력저하로 나타났다. 7세 이후에 시력검진을 처음 수행한 경우(OR=7.43, CI=2.84-19.39), 눈 이상 증상이 있는 경우(OR=3.08, CI=1.20-7.91), 아동연령이 어릴수록(OR=10.34, CI=3.25-32.85) 시력저하 경향이 높았고, 단말기를 주로 아래에서 위로 올려다보는 아동인 경우(OR=.08, CI=.02-.26), 시력저하 경향이 낮았다. 미취학아동의 시력저하에는 유전적인 요소도 중요하지만, 눈 이상 증상, 눈검사 시기, 단말기 사용방법, 아동의 연령과 관련성이 있었다. 그러므로 아동 양육기관과 보호자, 검진기관을 대상으로 아동의 눈 이상증상과 단말기 사용방법, 눈검사 시기에 대한 교육이 필요하며, 아동을 대상으로 한 시력저하예방을 위한 중재프로그램의 개발과 효과검증이 필요하다.

The study aimed to examine the state of visual acuity tests in preschoolers and determine the factors affecting the deterioration of their vision. A total of 172 pair, child aged 5-7 years and either one of their parents, were recruited from childcare centers or kindergarten between August 2015 and January 2016. Questionnaires were administered to the parents, and the children's visual acuities were measured. Using forward selection in logistics regression analysis, factors affecting vision deterioration were elucidated. Of 172 children, 128 (74.4%) had undergone a visual acuity test previously and 77 (44.8%) showed a deterioration in their vision. Children who had undergone their first visual acuity test after the age of 7 years (OR=7.425, CI=2.844- 19.385) and showed more abnormal eye symptoms, such as squinting or tilting the head to see or falling down frequently (OR=3.084, CI=1.202-7.914) and whose age was younger (OR=10.335, CI=3.252-32.848), were more likely to develop deterioration of vision. Children who had a posture such that they looked up at the computer monitor from below (OR=.075, CI=.022-.255), were less likely to show deterioration of vision. It can be inferred that early visual acuity tests is essential to detect deteriorated vision of preschoolers. Therefore, it is necessary to educate parents, personnels in day care center, and health clinics about the importance of early visual acuity tests and close observation of specific behaviors related to vision deterioration. Development of precautionary intervention program of vision deterioration in preschoolers and examination of its effects are needed.

현재 고속도로 도로표지의 글자 세로규격은 22~60cm로서 다양한 크기로 규정되어 있으나 글자 크기에 대한 산정근거를 찾을 수가 없고 운전자가 도로표지 정보를 정확하게 판독할 수 있는지 확인할 수가 없다. 운전면허시험에서 운전자가 갖추어야 할 시력은 0.5이상으로서 도로표지 글자크기도 운전자 최소시력인 0.5를 기준으로 설계되어져야 한다. 따라서, 최소시력 0.5의 운전자가 현행 도로표지 글자를 아무 문제없이 판독할 수 있는 지 검토가 필요하고 도로표지 글자크기를 결정할 수 있는 방법론 연구가 필요하다. 본 연구는 도로표지 글자 크기를 결정하는 방법론에 관한 연구로서 운전자 시각(시력), 제한속도, 행동판단시간, 편도차로수를 고려하여 시나리오를 설정하고 각 시나리오별 도로표지 글자크기를 결정하여 제시하였다. 고속도로 4차로 및 6차로 고속도로에서 행동판단시간 2.0초와 2.5초를 기준으로 시력 0.5인 운전자가 도로표지 글자를 효율적으로 판독하기 위해서는 글자크기 47 ~ 89cm 정도가 필요한 것으로 분석되었다. 고속도로 도로표지의 기존 글자크기는 운전자 최소시력을 기준으로 볼 때 작아서 판독하기가 어려운 것으로 분석되었다. 본 연구에서 개발된 방법론은 운전자 시력을 고려함으로써 도로표지 설계시 인적요인을 고려하였다는 점과 도로표지 글자 크기산정에 대한 근거를 제시하였다는데 그 의의가 있다.

At present the letter sizes of traffic sign are variously designated as 22 cm through 60 cm, however the basis for determination has not been found so far. Driver's visual acuity for getting a driver licence is required higher than 0.5. In order to interpret the information of traffic signs effectively, the minimum requirement of driver's visual acuity must be applied to determine the letter size of traffic sign. Therefore we reviewed that a driver with visual acuity of 0.5 could read the current letter sizes of traffic sign. In addition, a methodology was developed to determine the letter size of traffic sign satisfied with the driver's visual acuity of 0.5. This study established scenarios that were composed of visual acuity, reaction time, the number of lane and the letter sizes of traffic sign for each scenario were proposed. Current letter size of traffic sign would not be difficult for drivers with minimum visual acuity of 0.5 to recognize the contents or information of traffic signs. The method developed in this research has an advantage that can consider a human factor like driver's visual acuity for the design of traffic signs. There is also a meaning of making a basis for the letter size of traffic sign.

The purpose of this study was to verified the effects of exercise rehabilitation program on simple and complex medial collateral ligament(MCL) injuries in elite soccer players. Eight participants were assigned into 2 groups (simple MCL injury and complex knee joint ligaments injury). All participants were trained exercise rehabilitation program during 8weeks. The decision of peak torque, mean power and total work by Testing & Rehabilitation System was performed before and after exercise rehabilitation program. The results were compared before and after exercise rehabilitation program. The peak torque, mean power and total work were significantly improved after exercise rehabilitation in all groups. There was a slight increase in muscle strength in the complex injured group, but there was no significant difference between the two groups. These observation suggests that exercise rehabilitation program used this study have the possibility as effective rehabilitation program for improvement of performance in knee joint ligament injured elite soccer players.

The purpose of this study was to investigate the effects of after-school table tennis class on academic achievement and assessment of visual acuity of teenager. Subjects of the study were male middle school students who were divided into exercise group (n=11) and control group (n=11). Once a week, table tennis class of 90 minutes was carried out for 15 weeks. Analysis items were body composition, physical fitness (muscle strength, power, flexibility, and cardiorespiratory fitness), academic achievement (Korean, English, and Mathematics) and assessment of visual acuity (right and left). For data analysis, SPSS 18.0 was used to get the measured average ± standard error of each group by applying two-way ANOVA, independent t-test, paired t-test and Pearson's correlation. In the change of academic achievement, both two groups did not show a significant difference in the rank of Korean, English and Mathematics after the 15 weeks' table tennis class. Also, in the change of assessment of visual acuity did not showed a significant difference in exercise group. However. the result showed a significant positive correlation was in the relationship between physical fitness and academic achievement, as well as between academic achievement and %fat. These results combined showed that male middle school students' after school table tennis class had an effect on the relationship between physical fitness and academic achievement showed a positive correlation.

This study tried to investigate the difference of the legibility in different age groups (young and old) with same near visual acuity and to provide preliminary guidelines for the text sizes in the pesticides products based on the legibility experiments. To achieve the objective, legibility evaluation experiments were conducted to test the effects of different age(20s, 50-60s), gender, font type(thick gothic-type and fine gothic-type), thickness (plain and bold), and number of syllables(2 and 3 syllables) in the same near visual acuity(0.6). The results showed that legibility 50s was higher than 20s. And 20s are appealed higher discomfort than 50s. Considering these experimental results, it was recommended that the 14 pt or larger characters (100% readable size) should be used the important information such as toxicity, and the minimum character size was 7 pt (50% readable size) for other information.

Purpose: This purpose of study was to investigate the relationships among functional state, self-efficacy, and life satisfaction in the elderly with decreased visual acuity. Methods: The subjects were 162 elderly people from the G university hospital. Functional state was measured by Late-Life Function and Disability Instrument (LLFDI) and Minimum Data Set-Home Care version 2.0 (MDS HC 2.0). Self-efficacy and Life satisfaction were measured by the tool of Rho & Lee (2011) and Yoon (2007). Data were analyzed using t-test, ANOVA, Pearson's Correlation Coefficient, and logistic regression. Results: The daily life function was significantly associated with self-efficacy and vision decrease. The regression model with these two variables explained 35.6% of the variance of daily life function. IADL was significantly associated with vision decrease, age, gender, and self-efficacy. The regression model with the three variables explained 52.9% of the variance of IADL. Life satisfaction is significantly associated with self-efficacy, daily life function, vision decrease and IADL. The last regression model with the four variables explained 51.8% of the variance of life satisfaction. Conclusion: The levels of functional state, self-efficacy and life satisfaction in the elderly with decreased visual acuity were low. Self-efficacy was an important factor that influences on the functional state and life satisfaction. Therefore, nursing interventions that can enhance the self-efficacy are required in order to increase the functional state and life satisfaction in the elderly with decreased visual acuity.

Method : Using annual statistics of major surgeries provided by the National Health Insurance Corporation, it figured out what changes come in visual acuity by the number of cataract surgeries nationwide plus age, gender, and geriatric disease every 3 years from 2013 to 2019 through joint point regression for statistics. Objective : This study is intended to identify the relationship between geriatric diseases (diabetes, hypertension, obesity) and visual acuity in geriatric cataract surgery patients. Result : First, geriatric diseases of cataract surgery patients were closely related to diabetes, hypertension, obesity, smoking, and drinking. In particular, diabetes, hypertension, and smoking had a high prevalence rate. There was no difference in gender and age. Second, 72% of all geriatric cataract surgeries were performed at the clinic level, and intraocular lens that was used after geriatric cataract surgery accounted for the majority of monofocal intraocular lens as 96.6%. Third, the visual acuity in geriatric cataract surgery patients improved from an average of 0.40 before surgery to 0.06 after surgery, and visual acuity improvement was found in 95% of them. These results suggest that geriatric cataract patients can expect visual acuity stabilization and positive visual acuity improvement through early surgery.

Dynamic visual acuity is used as an important factor to measure athletic performance in sports field. A study on visual acuity testing system using non-see head mounted display (NST-HMD) was conducted recently. However, the NST-HMD has a problem that the sense of space felt by the subject differs from the actual environment. This is because the view is blocked so that it is only implemented in a virtual space. This paper proposes a dynamic visual acuity testing system using optical see through head mounted display (OST-HMD). To do this, OST-HMD and NST-HMD comparative tests were conducted using existing K-D (King-Devick) charts. Experiments were performed on 30 subjects and their visual acuity was measured and analyzed by parametric statistics and one-sample T-test. The results of the study demonstrate the effectiveness of the proposed OST-HMD. This study is expected to use the visual inspection and training equipment of OST-HMD.

For 299 patients who had undergone cataract surgeries we investigated the difference in visual acuity and refractive power before and after cataract surgery and the clinical change of the visual acuity and the refractive power according to age, gender, hospital visit time and specific medical history. We found the factors affecting preoperative and postoperative outcomes of the cataract patients in metropolitan hospitals by input, process, and outcome and analyzed medical characteristics and patient characteristics as the input variables. T-test and ANOVA have been performed for statistical analysis of functional status, and general status and the technical characteristic as the process variable and the outcome variable of diagnosis. Visual acuity improved significantly in patients who had undergone cataract surgery. However, the change in refractive power did not show a statistically significant difference but only a slight difference. The improvement of male patients was greater than that of female patients. The difference in age was more effective in patients under 50 years old and the effect of cataract surgery was relatively high in patients without the presence of specific medical history. Cataract surgery did not seem to help all of the patients, but it is more effective in improving visual acuity and refractive power. We conclude that simultaneous cataract surgery in both eyes is reasonable in order to have at least the better effect.

Purpose: This study is an investigation of the effects of long-term smart phone usage and of stretching on muscle stiffness, concentration, and visual acuity. Methods: Forty healthy young adults voluntarily participated in the study and were measured for muscle stiffness, concentration, and visual acuity before smartphone usage and after 30 minutes, 60 minutes, and 90 minutes of smartphone usage. The participants were randomly allocated to the intervention group (n=20) and the control group (n=20). Five minutes after the stretching exercise and eye exercise intervention, the participants were remeasured. Results: After long-term smartphone usage, increases in muscle stiffness and concentration were statistically significant (p<0.05), whereas decreases in visual acuity were statistically significant (p<0.05). After the stretching exercise and eye exercise intervention, muscle stiffness significantly decreased (p<0.05) and visual acuity significantly increased (p<0.05). Concentration, according to the stretching exercise and eye exercise intervention, showed no significant pre- or post-test difference. Conclusion: The results from this study indicate that long-term smartphone usage effectively improved concentration but increased muscle stiffness and decreased visual acuity. Appropriate stretching and eye movement during long-term smartphones usage should mitigate the effects on muscle stiffness and visual acuity. Furthermore, smartphones should be considered an effective tool for concentration training when coupled with the development of appropriate applications.

Dengue fever is a viral disease that is transmitted by mosquitoes and affects humans. In rare cases,dengue fever can cause visual impairment, which usually occurs within 1 month after contracting denguefever and ranges from mild blurring of vision to severe blindness. Visual impairment due to dengue fevercan be detected through angiography, retinography, optical coherence tomography (OCT) imaging,electroretinography, event electroencephalography (visually evoked potentials), and visual field analysis. The purpose of this study is to report changes in the eye captured using fluorescein angiography,indocyanine green, and OCT in 3 cases of dengue fever visual impairment associated with consistent visualsymptoms and similar retinochoroidopathic changes. The OCT results of the three patients with denguefever showed thinning of the outer retinal layer and disruption of the inner segment/outer segment (IS/OS)junction. While thinning of the retina outer layer is an irreversible process, disruption of IS/OS junction isreported to be reversible. Follow-up examination of individuals with dengue fever and associated visualimpairment should involve the use of OCT to evaluate visual acuity and visual field changes in patients withacute choroidal ischemia.

Purpose: To investigate the association between binocular function and vision after cataract removal and primary posterior chamber intraocular lens (PC-IOL) implantation in children with unilateral cataract and to identify visual function differences according cataract type. Methods: Clinical records of 2- to 6-year-old patients with unilateral cataract removal and primary PC-IOL implantation were reviewed retrospectively. Visual acuity and ocular alignment were measured. Sensory fusion was assessed with the Worth 4-dot test, and stereoacuity with the Titmus stereo test. Cataracts were classified according to cause, lens opacity location, age at onset, and presence of strabismus. Clinical characteristics of patients who obtained good visual function were identified. Results: Forty-seven patients were included. Among 22 (46.8%) with good vision (20/40 or better), only 6 (27.3%) achieved good binocular function (the presence of fusion and 100 seconds of arc or better of stereoacuity). Visual acuity was better in eyes with good binocular function (p=0.002). No other variables were significant for achieving good binocular function. Conclusions: The removal of unilateral cataract in a visually immature child can result in a combination of good visual acuity and binocular function. Good binocular function is closely related to good visual acuity.

Purpose: Macular edema, serous retinal detachment, and retinal pigment epithelial detachment have been reported in patientswith nephrotic syndrome. However, there is limited data about macular thickness in children with nephrotic syndrome. The aim of this study was to compare the mean macular thickness in children with nephrotic syndrome and in a control groupand to correlate it with visual acuity and level of proteinuria. Methods: The comparative cross-sectional study included 66 children aged 6 to 17 years with nephrotic syndrome andhealthy control seen in two tertiary centers in Malaysia. We recorded demographic data, as well as visual acuity, level of proteinuria,and the mean macular thicknesses in both groups. The mean macular thickness was measured using Stratus opticalcoherence tomography according to nine areas of the Early Treatment Diabetic Retinopathy Study map. Results: The mean foveal thickness was 238.15 ± 22.98 μm for children with nephrotic syndrome and 237.01 ± 22.60 μm forthe control group. There was no significant difference in the mean macular thickness between the groups (p = 0.843). A significantcorrelation with visual acuity was observed in the superior outer macula (r = ?0.41, p = 0.019), the nasal outer macula(r = ?0.41, p = 0.019), and the inferior outer macula (r = ?0.40, p = 0.021). There was no significant correlation between themean macular thickness and level of proteinuria (p = 0.338), although those with higher levels of proteinuria demonstrated atrend towards increased macular thickness. Conclusions: The mean macular thickness in children with nephrotic syndrome was similar to that of healthy children. A significantcorrelation between the mean thickness of the outer macular layer and the presenting visual acuity was observed. There was no correlation between the mean macular thickness and the level of proteinuria.

Purpose: To evaluate the association between degree of retinal abnormalities and uncorrected visual acuity(UCVA) in idiopathic epiretinal membrane (ERM) patients with a small amount of refractive error. Methods: We retrospectively reviewed 49 eyes (37 patients) of idiopathic ERM patients. We investigated theassociation between visual acuity and macular status (central macular thickness [CMT], outer retinal integrityscore, and inner retinal irregularity index) that was assessed by optical coherence tomography using multiplelinear regression analysis. We defined visual acuity difference (VAD) as the difference between UCVA andbest-corrected visual acuity (BCVA). We divided patients into two groups according to VAD size and comparedclinical characteristics between the two groups. We also investigated factors associated with VAD usingmultiple linear regression analysis. Results: BCVA showed significant association with CMT and outer retinal integrity score, while UCVA showedsignificant association with CMT and inner retinal irregularity index. Patients with a large VAD showed a similarlevel of BCVA compared to the small VAD group (logarithm of the minimum angle of resolution [logMAR],large VAD group 0.11 ± 0.11 vs. small VAD group 0.13 ± 0.12, p = 0.585). However, UCVA was worse (logMAR,large VAD group 0.44 ± 0.14 vs. small VAD group 0.18 ± 0.14, p < 0.001) and inner retinal irregularity was higher(large VAD group 1.06 ± 0.04 vs. small VAD group 1.04 ± 0.03, p < 0.001) in patients with a large VAD. Onmultiple linear regression analysis, the absolute value of spherical equivalent (standardized coefficient β 0.521,p < 0.001) and inner retinal irregularity index (standardized coefficient β 0.448, p < 0.001) were significantlyassociated with VAD. Conclusions: UCVA was associated with inner retinal irregularity in idiopathic ERM patients with a mild degreeof refractive error. Inner retinal irregularity was also associated with degree of VAD, suggesting that the effectof refractive error correction is greater in patients with more distorted retina.

Purpose: To investigate the efficacy of a computerized visual acuity test, the SNU visual acuity test for children. Methods: Fifty-six children, ranging from 1 to 5 years of age, were included. In a dark room, children gazed at and followed a circular dot with 50% contrast moving at a fixed velocity of 10 pixels/sec on a computer monitor. Eye movement was captured using a charge coupled device camera and was expressed as coordinates on a graph. Movements of the eye and dot were superimposed on a graph and analyzed. Minimum visualized dot diameters were compared to the Teller visual acuity. Results: Ten eyes (8.9%) of six children failed to perform the Teller visual acuity test, and two eyes (1.8%) of one patient failed to perform the SNU visual acuity test. The observed Teller visual acuity and SNU visual acuity were significantly correlated (p <0.001). Visual angle degrees converted from the Teller visual acuity and SNU visual acuity were also significantly correlated (p < 0.001). Conclusion: The SNU visual acuity using moving targets correlated well with Teller visual acuity and was more applicable than the Teller acuity test. Therefore, the SNU visual acuity test has potential clinical applications for children.

Purpose: To investigate correlated factors on final visual acuity in conjunction with fluorescein angiography (FA)and optical coherence tomography (OCT) findings of chronic central serous chorioretinopathy (CSCR). Methods: Twenty-four patients (36 eyes) with typical findings of chronic CSCR based on medical records, FA and OCT results were enrolled in this study. We investigated demographic findings, initial and final visual acuity (VA),and some typical findings of FA including the type of leakage pattern, the existence of a gravitational tract and an abnormal hyperfluorescent area centered on the fovea. We also investigated OCT findings to examine serous retinal detachment, outer photoreceptor layer (OPRL) preservation, continuity of the inner segment (IS) and the outer segment (OS) of the photoreceptor layer in case of macular attachment, and other typical findings. The converted logarithm of the minimum angle of resolution VA was used to investigate the statistical correlation with these FA and OCT findings. Results: An abnormal hyperfluorescent area within 1 macular photocoagulation study disc area on FA and cystoid degeneration on OCT were correlated with poor final VA of less than 20 / 40. However, the preserved OPRL and the continuity of IS / OS junction were correlated with a good final VA of 0.5 or more. Conclusions: These specific findings could be associated with recurrent or persistent subretinal fluid and could be important parameters of decision for treatment.