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1.
Sci Rep ; 14(1): 826, 2024 01 08.
Article in English | MEDLINE | ID: mdl-38191660

ABSTRACT

To analyze the status of binocular visual functions, the relationship between binocular visual function and computer vision-related symptoms in the high-tech industry group. The study sample was comprised of 33 participants aged between 20 and 40 years of age. After completing basic information and the Computer Vision Symptom Scale (CVSS-17) questionnaire, the participants underwent a comprehensive examination of binocular visual function. All data were statistically analyzed with SPSS V26.0 software. The value of the binocular vision function of the Taiwan high-tech industry group was significantly different compared with the Scheiman and Morgan standard value. Study subjects were generally found to exhibit larger exophoric at distance, which in turn might lead to a lower ability to maintain binocular fusion to a single image, or recover from fusional disruption at distance. Subjects also experienced accommodation and convergence problems at near at the same time. Age, gender, and refractive errors had no significant impact on CVSS-17 scores, only the duration of computer usage showed a significant effect, particularly for internal symptom factor (ISF) dimensions. In addition, the interaction between the ISF and external symptom factor resulted in more severe visual symptoms. Long-term use of electronic devices may lead to an imbalance in binocular vision function, thereby increasing or exacerbating visual symptoms. If the use of electronic devices is an unchangeable trend, interventions in prescription, visual training or the visual design of electronic products become worthwhile topics for development.


Subject(s)
Computers , Vision, Binocular , Humans , Young Adult , Adult , Taiwan , Software , Accommodation, Ocular , Intrinsic Factor
2.
Sci Rep ; 13(1): 19444, 2023 11 09.
Article in English | MEDLINE | ID: mdl-37945680

ABSTRACT

This study investigated the influence of large-diameter multifocal contact lenses on the ocular surface, visual quality, and visual function for presbyopic adults with dry eye syndromes. The study enrolled 40-55-year-old adults with presbyopia and dry eye syndromes (DES). The subjects were randomly assigned to three groups wearing different designs of contact lenses (Proclear, SMR, and Optimum) for 6-8 h a day for two weeks. Ocular surface health, tear quality, visual quality, and visual function were measured before and after lens wear. No significant difference was observed across all three groups for the amount of conjunctival redness, blink frequency (lens on), and stereopsis vision before and after wearing. Although there seemed to be a significant declining trend for corneal staining and limbal redness, non-invasive tear break-up time (TBUT), and lipid layer thickness while lens wear, the measured values were all within the normal range. Vice-versa after lens removal, results also showed significant improvement on lipid layer thickness, blink frequency (lens off), and contact TBUT. A significant improvement was observed in the modulation transfer function (MTF) of the total area ratio after wearing contact lenses. In contrast, the MTF of the high-order aberration area ratio resulting from lens wear was lower than that of the baseline measurement. There are also significant improvements observed for SMR and Optimum regarding near visual acuity, near point of accommodation, and the subjective questionnaire (OSDI and VBP) scores. Although it is difficult to avoid a specific negative impact on the ocular surface and tear film, visual function and visual quality can still be positively improved, especially shown on larger diameter and distance-center designed multifocal contact lenses.


Subject(s)
Contact Lenses , Dry Eye Syndromes , Presbyopia , Humans , Adult , Middle Aged , Vision, Ocular , Dry Eye Syndromes/therapy , Presbyopia/therapy , Lipids , Tears
3.
Ophthalmic Physiol Opt ; 43(6): 1356-1363, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37476932

ABSTRACT

PURPOSE: The aim of this study was to examine the quality of assessment and the utilisation of optical low vision aids (OLVAs) among people with visual impairment (VI) in Taiwan. METHODS: The study included 577 participants between 4 and 100 years of age (314 males and 263 females). All participants had been certified by the Ministry of the Interior of Taiwan, indicating that they had undergone a thorough and comprehensive low vision assessment, including evaluation of visual acuity (VA), contrast sensitivity, colour vision, visual fields and glare disability. Furthermore, all participants who consented to refraction had received prescriptions for OLVAs. RESULT: All participants were prescribed one or more OLVAs such as eyeglasses, tinted lenses, magnifiers, closed-circuit television magnifiers, telescopes, or screen magnifiers. Among the 577 individuals, 515 received correction for refractive errors, providing the best-corrected VA (BCVA). The improvement in VA was significant at both distance and near, improving from 1.29 ± 0.55 to 1.01 ± 0.52 logMAR (p < 0.001) and from 1.29 ± 0.56 to 1.01 ± 0.52 logMAR (p < 0.001), respectively. Eyeglasses were the primary OLVAs chosen by 333 participants (64.7%), while 53.3%-80.3% of participants combined eyeglasses with other OLVAs to enhance their visual performance. CONCLUSIONS: The most commonly used and effective OLVA was eyeglasses. Skilfully utilising appropriate refractive and VA measurements is crucial for determining the most suitable and beneficial OLVA for individuals with VI.

4.
Int Ophthalmol ; 43(9): 3309-3319, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37329407

ABSTRACT

PURPOSE: Glare visual acuity and contrast sensitivity are important indicators of visual quality. Studies have shown that the glare visual acuity and contrast sensitivity in dry eye patients tend to degenerate, further affecting their quality of life. The objective of this study was to investigate the effect of notch filters on glare VA and contrast sensitivity in patients with dry eye or with dry eye syndrome. METHOD: 36 subjects in the 20‒65 age group were diagnosed as having dry eye disease or perceived dry eye syndromes themselves who were included after the initial screening with the OSDI questionnaire, and one was subsequently excluded as they had undergone retinal detachment surgery. Finally, 35 subjects (14 male and 21 female) with a mean age of 40.66 ± 15.62 years participated in this study. All subjects wore their habitual prescriptions and four different filter lenses (namely 480, 620, dual 480 & 620 notch filter, and FL-41 tinted lens), and measured the parameters of glare visual acuity and contrast sensitivity using CSV-1000 and sine wave contrast test (SWCT), respectively. Student t-test and Repeated measurement analysis (R-ANOVA) were utilized by using SPSS 26.0 software. RESULTS: A dual-wavelength 480 & 620 nm optical notch filter had a significant anti-glare effect decreasing glare disabilities or discomfort, and leading to better visual quality, the same effect was also shown on a 480 nm notch filter lens. All participants showed a significant difference among the baseline, three notch filters (480 nm, 620 nm, dual-wavelength 480 & 620 nm), and FL-41 tinted lens were used on SWCT_A (1.5 cpd, F = 3.054, p = 0.019) and SWCT_E (18 cpd, F = 2.840, p = 0.049); but did not show statistical different on SWCT_B (3 cpd, F = 0.333, p = 0.771), SWCT_C (6 cpd, F = 1.779, p = 0.159), and SWCT_D (12 cpd, F = 1.447, p = 0.228). The baseline showed the best visual performance on CS at a low spatial frequency (SWCT_A, 1.5 cpd), any filter might reduce the contrast sensitivity at low spatial frequencies in the clinical trial, whereas 480 nm notch filter showed the best effectiveness on CS at a high spatial frequency (SWCT_E, 18 cpd), the FL-41 lens that also filters out the 480 nm band does not achieve the same effect. Moreover, patients with dry eye or those older than 40 years old preferred optical multilayer notch filters to FL-41 tinted lenses. CONCLUSION: The 480- & 620-nm dual-wavelength and 480-nm single-wavelength notch filters have the best effect on the glare visual acuity and contrast sensitivity (CS) at high spatial frequencies in dry eye patients. The 620-nm notch filter performs better in CS at low and mid-low spatial frequencies; the FL-41 tinted lens performs poorly for glare VA and CS spatial frequencies examination. Patients with glare disabilities or CS disturbance at high spatial frequencies may choose a 480-nm notch filter lens, and patients who have CS disturbance at low spatial frequencies may consider a 620-nm notch filter for the prescription.


Subject(s)
Contrast Sensitivity , Dry Eye Syndromes , Humans , Male , Female , Adult , Middle Aged , Quality of Life , Visual Acuity , Glare , Dry Eye Syndromes/diagnosis
5.
BMC Ophthalmol ; 23(1): 47, 2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36726067

ABSTRACT

BACKGROUND: Morgan and Scheiman's Optometric Extension Program (OEP) expected binocular vision findings have longstanding use in optometry. With technological advances, the demands and standards of binocular function have changed. This study aimed to investigate which binocular visual functions can effectively predict visual behavior performance. METHODS: Participants aged 15-24 years were recruited from two colleges and two universities. After completing the CSMU-Visual Behavioral Performance questionnaire (CSMU-VBP, with four components: near work, visual perception, visual comfort, and whole-body balance), participants were divided into symptomatic and asymptomatic groups based on questionnaire findings (cutoff: < 12 vs. ≥ 12 symptoms). Then a 24-step binocular visual examination was undertaken. Data were analyzed with one-sample, Student's, and paired t-tests. Additionally, receiver operating characteristic analysis was used to determine the predictors of binocular visual function required for near work, visual perception, visual comfort, and body balance dimensions. RESULTS: Among 308 participants, 43 (14%) and 265 (86%) were symptomatic and asymptomatic, respectively. Among the 46 participants with abnormal binocular vision, 36 (78%) reported that they had no obvious symptoms. The commonest dysfunctions were accommodative excess and convergence excess. Most of the binocular visual findings significantly diverged from traditional normal values: amplitude of accommodation, as well as base-in prism to break and recovery points at distance were higher than traditional normal values, whereas others were lower than traditional normal values. Total CSMU-VBP scores indicated that the asymptomatic and symptomatic groups had significant differences in DBO recovery (t = 2.334, p = 0.020) and BAF (t = 1.984, p = 0.048). Receiver operating characteristic curve analysis yielded the following binocular visual functional cutoff points: near work (DBO blur < 7, DBO recovery < 5.5), visual perception (MAF < 10.5, BAF < 10.25), visual comfort (DLP < - 2.25, DBI break > 11.5, NBI blur > 15, NBI break > 17.5, NBI recovery > 13, NPC < 5.75), and body balance (NFD_H > - 0.5, gradient AC/A [minus] > 2.25, NPC < 4.75). CONCLUSIONS: The mean values of binocular visual function among young Taiwanese adults were statistically different from traditional normative values. Further research is required to confirm whether these findings reflect impaired binocular vision or stringent criteria. Assessments of binocular visual function, especially binocular accommodation sensitivity, are crucial in routine optometric examination.


Subject(s)
Convergence, Ocular , Ocular Motility Disorders , Humans , Adult , Accommodation, Ocular , Vision, Binocular , Vision Disorders/diagnosis
6.
J Clin Med ; 11(9)2022 Apr 23.
Article in English | MEDLINE | ID: mdl-35566498

ABSTRACT

PURPOSE: According to previous studies, the prevalence rate of cataracts has increased in recent years. This study aims to investigate and analyze the risk factors of early-onset cataracts in Taiwan. METHODS: A total of 71 subjects aged between 20 and 55 were diagnosed with cataracts in a medical center. Participants were divided into three groups: control, early-onset cataract (EOC), and combined (EOC combined with dry eye) groups. Eye examinations including autorefraction, best-corrected visual acuity (BCVA), subjective refraction, axial length, fundus, slit lamp, and reactive oxygen species (ROS, including total antioxidative capacity, TAC; C-reactive protein, CRP; and glutathione peroxidase, GPx) were performed. In addition, a questionnaire on patient information, history, habits, family history, and Depression Anxiety Stress Scales (DASS) was completed before the examination. RESULTS: 27 non-EOC (control group), 20 EOC, and 24 combined patients participated in the study. Compared with the control group, Body Mass Index (BMI), gender, educational level, hypertension, diabetes, hyperlipidemia, chronic pain, and body-related diseases were significantly different between the three groups. Family history was also significantly different: family heart disease, hypertension, asthma, allergies, stroke, and immune system were also significantly different. In addition, subjects who took hypertensive drugs, antihistamines, and other medications were also significantly different. Statistical analysis indicated that best corrective visual acuity and the spherical equivalent were significantly different between the three groups. Similar results were found in CRP blood analysis. DISCUSSION AND CONCLUSION: According to the results, EOC may result from systemic diseases. The risk corresponded to an increase in ROS blood analysis. Furthermore, eye drops and medicine intake significantly influenced EOC patients. To prevent or defer early-onset cataracts, monitoring physical health, CRP, and GPx analysis may be worth considering in the future.

7.
J Clin Med ; 11(9)2022 May 06.
Article in English | MEDLINE | ID: mdl-35566750

ABSTRACT

Purpose: The transition of Taiwan from an aging to a super-aging society has come with a cost as more elderly now suffer from cognitive impairment. The main purpose of our study was to investigate if early detection can be developed so that timely intervention can be instituted. We analyzed the correlation of cognitive function with ocular physiology and visual functions between senior citizens aged 60 years or older in Taiwan. Methods: Thirty-six healthy subjects were recruited for the study. Addenbrooke's cognitive examination III (ACE-III), binocular functions (including objective and subjective refraction, distance and near dissociated phoria, stereopsis, contrast sensitivity, adult developmental eye movement (ADEM), and ocular physiology (by using optical coherence tomography, OCT, and macular pigment measurement, MPS) were performed, and the data were analyzed via independent t-test, chi-square test, Pearson correlation, linear regression, and ROC (receiver operating characteristic) curve. Results: Data analysis showed that (1) patients with poor eye movement had a strong correlation with the total score and all dimensions of cognitive functions, (2) the thickness of the macula had a strong correlation with attention and memory, and (3) patients with poor eye movement and poor stereopsis in combination with thinner inferior macula appeared to have lower cognitive abilities. Discussion and Conclusions: Cognitive dysfunction is not readily identified during the early stage of cognitive decline. The use of simple and inexpensive ADEM or stereopsis test and comparing the OCT results that are popular in optometry clinics for reference can be diagnostic in identifying patients with mild cognitive impairments. With the combined use of macular pigment density or retinal thickness measurements, it was possible to effectively predict the early degradation of cognition.

8.
Sci Rep ; 12(1): 6573, 2022 04 21.
Article in English | MEDLINE | ID: mdl-35449200

ABSTRACT

Theoretically, contact lenses change the accommodation and vergence demands of the eyes and directly or indirectly influence binocular vision. The purpose of this study was to investigate the influence of different optical designs of contact lenses on binocular vision and visual behavior among young adults. In this randomized, single-blinded experimental study, visual behavioral performance (VBP) and Ocular Surface Disease Index questionnaires were used for preliminary screening. Nineteen myopic subjects aged 20-26 years (21.59 ± 1.40 years) participated in the study. Baseline values for subjective refraction and binocular visual functions were evaluated. All the subjects were randomly grouped to wear different optical designs of single-vision, progressive, and bifocal contact lenses. Eye examinations were performed on the first day (CL baseline), 2nd week, and 4th week of wearing the lenses. In addition, subjects completed the VBP and visual quality questionnaire again at the end of the examination. Single-vision contact lenses (Lens 1) increased accommodative lag, negative relative accommodation, and distant and near vergence; however, vergence facilities, accommodative facilities, heterophoria, and the comfort and posture balance dimensions in the VBP questionnaire were improved. Progressive contact lenses (Lens 2) reduced the lag of accommodation and near vergence; in addition, vergence facilities and accommodative facilities were also improved. Bifocal contact lenses (Lens 3) affected negative and positive relative accommodation, but vergence facilities and accommodative facilities also progressed. Furthermore, both progressive (Lens 2) and bifocal (Lens 3) contact lenses enhanced overall visual behavioral performance. In terms of visual quality, single-vision contact lenses (Lens 1) were the most comfortable, progressive and bifocal contact lenses reduced distant visual acuity and stability, progressive contact lenses (Lens 2) had more complaints about halos at night, and bifocal contact lens (Lens 3) users were more likely to have double vision. Compared with single-vision contact lenses, progressive and bifocal contact lenses relaxed accommodation, reduced the lag of accommodation, and improved visual behavioral performance. Although the vergence function showed a significant change, it did not show worse trends when wearing contact lenses. Contact lenses with different optical designs have a great influence on binocular vision and visual behavioral performance.


Subject(s)
Contact Lenses , Vision, Binocular , Accommodation, Ocular , Humans , Vision Tests , Visual Acuity , Young Adult
9.
Healthcare (Basel) ; 10(1)2021 Dec 23.
Article in English | MEDLINE | ID: mdl-35052184

ABSTRACT

Purpose: With the benefits of advanced medical technology, Taiwan has gradually changed from an aged society to a super-aged society. According to previous studies, the prevalence rate of mild cognitive impairment (MCI) over the age of 60 is 15% to 20%. Therefore, the main purpose of our study was to analyze the correlation of cognitive function with visual function (specifically, binocular vision and visual perception) in Taiwanese volunteers aged 60 years or older. Methods: Thirty-six healthy participants who were not taking psychiatric medications and who had not been diagnosed with any retinal or optic nerve diseases were enrolled. Addenbrooke's cognitive examination III (ACE-III), binocular visual function, and visual perception evaluation were performed, and the data analyzed statistically by t-test, χ2, linear regression, and MANOVA. Results: Cognitive function was closely correlated with visual function and visual perception; the horizontal adjustment time of binocular eye movement, stereopsis, the motor-free visual perception test-4 (MVPT-4), and peripheral awareness actually displayed higher explanatory power in predicting cognitive function. In addition, various interactive parameters between visual function and visual perception were found to affect specific aspects of ACE-III. Discussion: Our study revealed that there was a close correlation of cognitive function with visual function; as such, it may be possible to predict visual function deficits in patients with mild cognitive impairment.

10.
J. optom. (Internet) ; 13(4): 249-256, oct.-dic. 2020. tab, graf
Article in English | IBECS | ID: ibc-201489

ABSTRACT

According to Taiwan optometry act, low-vision services, such as refractive correction and low vision assessment, are now included in Optometric profession. This study was designed to investigate the efficiency of refractive correction and the relationship between refractive correction, eye diseases, visual symptoms, and optical device selection for patients with low vision. METHODS: This study involved a total of 220 participants aged from 7 to 99, with 119 males and 101 females. All of them were referred from three institutes of Taiwan Resource Portal of Assistive Technology under the supervision of the Ministry of Health and Welfare during Feb 2016 to Jan 2018. Accordingly, 42, 76, and 102 of the participants were identified as having mild, moderate, and severe visual impairments, respectively, by five experienced and licensed optometrists for this comprehensive low vision examination. RESULTS: The most common eye diseases in this study were retinal disease, cataract, glaucoma, and optic nerve hypoplasia; some of the participants had multiple eye diseases while participating in the study. Except visual acuity decrease, eye diseases were highly correlated with participants' visual symptoms. Refractive correction is the first step in low-vision examination, therefore, it might be much helpful to some types of eye diseases, visual symptoms, and to the decisions of optical devices for low-vision patients. The results herein suggest that color vision and contrast sensitivity should be taken into consideration when calculating the second optical magnifying power after refractive correction. CONCLUSIONS: Refractive correction is necessary for the treatment of patients' visual symptoms and also for the prescription of low-vision aids


Con arreglo a la ley de Optometría de Taiwán, los servicios de baja visión, tales como la corrección refractiva y la evaluación de la baja visión, se incluyen ahora en la profesión optométrica. Este estudio fue diseñado para investigar la eficiencia de la corrección refractiva y la relación entre corrección refractiva, enfermedades oculares, síntomas visuales, y selección del dispositivo óptico para pacientes con baja visión. MÉTODOS: Este estudio incluyó a un total de 220 participantes, 119 varones y 101 mujeres, con edades comprendidas entre 7 y 99 años. Todos ellos procedían de tres institutos del Portal de Recursos de Tecnología Asistencial de Taiwán, bajo la supervisión del Ministerio de Sanidad y Bienestar, desde febrero de 2016 a enero de 2018. En total, se identificaron 42, 76, y 102 participantes con trastornos visuales leves, moderados y graves, respectivamente, por parte de cinco optometristas experimentados y licenciados, para este amplio examen de baja visión. RESULTADOS: Las enfermedades oculares más comunes en este estudio fueron: enfermedad retiniana, cataratas, glaucoma, e hipoplasia del nervio óptico. Algunos de los participantes tenían enfermedades oculares múltiples cuando participaron en el estudio. Exceptuando la disminución de la agudeza visual, las enfermedades oculares guardaron una alta correlación con los síntomas visuales de los participantes. La corrección refractiva es el primer paso del examen de la baja visión y, por tanto, podría resultar muy útil para ciertos tipos de enfermedades oculares, síntomas visuales, y para la toma de decisiones sobre los dispositivos ópticos para los pacientes con baja visión. Los resultados del presente estudio sugieren que la visión del color y la sensibilidad al contraste deberían tenerse en consideración a la hora de calcular la segunda potencia de magnificación óptica tras la corrección refractiva. CONCLUSIONES: La corrección refractiva es necesaria para el tratamiento de los síntomas visuales de los pacientes, y también para la prescripción de dispositivos ópticos para los pacientes con baja visión


Subject(s)
Humans , Male , Female , Child , Adolescent , Young Adult , Adult , Middle Aged , Aged , Aged, 80 and over , Optometry , Refractive Errors/diagnosis , Refractive Errors/rehabilitation , Vision, Low , Optical Devices , Eye Diseases/classification , Eye Diseases/diagnosis , Visual Acuity , Vision Tests , Taiwan
11.
J Optom ; 13(4): 249-256, 2020.
Article in English | MEDLINE | ID: mdl-31787520

ABSTRACT

According to Taiwan optometry act, low-vision services, such as refractive correction and low vision assessment, are now included in Optometric profession. This study was designed to investigate the efficiency of refractive correction and the relationship between refractive correction, eye diseases, visual symptoms, and optical device selection for patients with low vision. METHODS: This study involved a total of 220 participants aged from 7 to 99, with 119 males and 101 females. All of them were referred from three institutes of Taiwan Resource Portal of Assistive Technology under the supervision of the Ministry of Health and Welfare during Feb 2016 to Jan 2018. Accordingly, 42, 76, and 102 of the participants were identified as having mild, moderate, and severe visual impairments, respectively, by five experienced and licensed optometrists for this comprehensive low vision examination. RESULTS: The most common eye diseases in this study were retinal disease, cataract, glaucoma, and optic nerve hypoplasia; some of the participants had multiple eye diseases while participating in the study. Except visual acuity decrease, eye diseases were highly correlated with participants' visual symptoms. Refractive correction is the first step in low-vision examination, therefore, it might be much helpful to some types of eye diseases, visual symptoms, and to the decisions of optical devices for low-vision patients. The results herein suggest that color vision and contrast sensitivity should be taken into consideration when calculating the second optical magnifying power after refractive correction. CONCLUSIONS: Refractive correction is necessary for the treatment of patients' visual symptoms and also for the prescription of low-vision aids.


Subject(s)
Cataract , Optical Devices , Refractive Errors , Vision, Low , Female , Humans , Male , Taiwan , Vision Tests
12.
Optom Vis Sci ; 90(4): 400-6, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23458978

ABSTRACT

PURPOSE: To investigate factors that may contribute to the myopization of urban elementary school students in Taiwan. METHODS: Grades 1 to 6 students of the same racial background (n = 1894; mean age, 6.3-11.3 years) in three schools, located in Tamsui, Taichung, and Tainan, were refracted to obtain the best corrected visual acuity. The refractive power needed for best corrected visual acuity was used for subsequent statistical analysis. On behalf of their children, parents also completed a questionnaire on six categories of potential myopization variables. Correlation between these variables and the increase or decrease in the refractive error was assessed. The predictive value of each variable was also calculated based on linear regression analysis. RESULTS: The overall mean refractive error in grades 1 to 6 was -0.37, -0.68, -1.33, -1.60, -1.90, and -2.51 D, respectively. The prevalence of myopia (-1.00 D or more minus) showed a significant difference between grades 2 and 3 and, again, between grades 5 and 6. In addition, 20 potential modulating factors were evaluated; 65.9% of the change in the refractive error could be explained by four: (1) lag in optimal correction, defined as a -1.00-D deficit between new refractive error and current optical correction; (2) outdoor spectacle wear; (3) spectacles for different working distances; and (4) hours spent on reading and writing on weekdays. In contrast, outdoor time and the intake frequency of 36 food items both held very low predictive values of 0.2% and 2.5%, respectively. CONCLUSIONS: Each variable associated with the refractive error has a different predictive value, either positive or negative. Ultimately, the interplay of these variables decides the outcome of the pattern and the degree of school myopia.


Subject(s)
Eyeglasses , Myopia/epidemiology , Refraction, Ocular/physiology , Schools , Students/statistics & numerical data , Urban Population/statistics & numerical data , Child , Female , Humans , Male , Myopia/physiopathology , Myopia/rehabilitation , Prevalence , Prognosis , Risk Factors , Surveys and Questionnaires , Taiwan/epidemiology
13.
Clin Exp Optom ; 95(5): 531-7, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22448958

ABSTRACT

PURPOSE: The aim was to screen children from Grades 1 to 6 in an urban elementary school in Central Taiwan for visual deficits and associated parameters and, as an extension, to examine the acceptance of cycloplegic therapy as well as the lag in optimal vision correction. METHODS: Of 900 students in one school, 731 participated in the study, with parental consent. Data from 694 students, who had also completed a vision correction history were analysed. In addition to body height and weight, the screening included vision, non-cycloplegic autorefraction and distance retinoscopy, axial length and functional testing. RESULTS: There was a decrease in students with vision of 1.0 or better from 55.8 per cent in Grade 1 to 20.0 per cent in Grade 6. The decreases between Grades 2 and 3 and Grades 5 and 6 were significant. These trends were in general agreement with those based on refractive error and axial length. The students had abnormal functional findings including: stereoscopic vision, 9.2 per cent; cover tests, 14.1 per cent; pupillary responses, 13.8 per cent; and less commonly in extraocular muscular functions (3.0 per cent) and colour vision (5.2 per cent). A full 40 per cent of students received cycloplegic therapy with 25 per cent dropping out for various reasons. These cases were generally associated with lower vision and higher myopia. A lag between subnormal vision and optical correction was also observed with 55.1 per cent apparently not optimally corrected. Other parameters, including body height, weight and body mass index were not correlated with vision or refractive error. CONCLUSIONS: Age-dependent increase in the prevalence of myopia appears to continue despite the common practice of topical cycloplegic therapy in Taiwan. Timely correction of the refractive error is also lacking. While maintaining a visual acuity of 1.0 or better for all students at all times is not possible, this lag might be shortened by more frequent screening and/or direct provision of optical aids.


Subject(s)
Vision Disorders/epidemiology , Body Height , Body Mass Index , Body Weight , Child , Humans , Mydriatics/therapeutic use , Refraction, Ocular , Taiwan/epidemiology , Urban Health , Vision Disorders/drug therapy , Vision, Ocular
14.
Phys Rev E Stat Nonlin Soft Matter Phys ; 68(2 Pt 2): 026612, 2003 Aug.
Article in English | MEDLINE | ID: mdl-14525138

ABSTRACT

The existence of passive metamaterials, in which the speed of light is greater than its speed in vacuum, is proposed. Analysis and numerical simulations demonstrate these trans-vacuum-speed (TVS) properties. A transmission line realization of a TVS medium is established. Excellent agreement between the results of the theoretical constructs and the corresponding transmission line models are demonstrated. A practical transmission line TVS metamaterial design is proposed and validated numerically, which could be used to confirm these results experimentally.

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