Abnormal tear dynamics and symptoms of eyestrain in operators of visual display terminals.
OBJECTIVES: To clarify the relation between the prevalence of dry eye syndrome and subjective symptoms of asthenopia in visual display terminal (VDT) operators. METHOD: 722 VDT workers (242 subject workers with symptoms of asthenopia and 480 controls without such symptoms) without obvious organic ocular diseases received an ophthalmological examination consisting of refractometry and a tear function (phenol red thread) test. RESULTS: More than 30% of symptomatic workers were found to meet the criteria of dry eye, and the odds ratio compared with the controls was 4.61 (p < 0.001). This odds ratio was significantly greater than that obtained for refractive errors (2.31). CONCLUSIONS: Although this cross sectional study could not prove that dry eyes are the cause of asthenopia, the profound association of dry eyes with symptoms of asthenopia could be verified. It would be useful to carry out tear function tests in workers with symptoms of asthenopia. (+info)
Sequelae of sarin toxicity at one and three years after exposure in Matsumoto, Japan.
In order to clarify the later sequelae of sarin poisoning that occurred in Matsumoto City, Japan, on June 27, 1994, a cohort study was conducted on all persons (2052 Japanese people) inhabiting an area 1050 meters from north to south and 850 meters from east to west with the sarin release site in the center. Respondents numbered 1237 and 836 people when surveys were conducted at one and three years after the sarin incident, respectively. Numbers of persons with symptoms of sarin toxicity were compared between sarin victims and non-victims. Of the respondents, 58 and 46 people had symptoms associated with sarin such as fatigue, asthenia, shoulder stiffness, asthenopia and blurred vision at both points of the survey, respectively. The prevalences were low; some complained of insomnia, had bad dreams, difficulty in smoking, husky voice, slight fever and palpitation. The victims who had symptoms one year after the incident had a lower erythrocyte cholinesterase activity than did those who did not have symptoms at the early stage; such persons lived in an area with a 500 meter long axis north east from the sarin release site. The three-year cohort study clearly showed that the odds ratios of almost all of the symptoms were high in the sarin-exposed group, suggesting a positive relationship between symptoms and grades of exposure to sarin. These results suggest that symptoms reported by many victims of the sarin incident are thought to be sequelae related to sarin exposure. (+info)
Work-related vision hazards in the dental office.
Among the numerous threats to the dentist's health there is one relating to the eye. The paper discusses the impact of selected adverse factors on the eye in connection with dental practice in the surgery. (+info)
Effects of black current anthocyanoside intake on dark adaptation and VDT work-induced transient refractive alteration in healthy humans.
The effects of oral intake of a black currant anthocyanosides (BCA) concentrate on dark adaptation, video display terminal (VDT) work-induced transient refractive alteration, and subjective asthenopia symptoms (visual fatigue) were examined in a double-blind, placebo-controlled, crossover study with healthy human subjects. In a dark adaptation study, intake of BCA at three dose levels (12.5-, 20-, and 50 mg/subject, n = 12) appeared to bring about dose-dependent lowering of the dark adaptation threshold. Statistical analysis comparing the values before and after intake indicated there was a significant difference at the 50 mg dose (p= 0. 011). Comparing the refraction values for the dominant eye, BCA intake (50 mg/subject, n = 21) resulted in no decrease in the average value after the visual task; whereas, a placebo trial resulted in a large decrease in the average value, resulting in borderline significance (p = 0.064). In the assessment of subjective asthenopia symptoms by questionnaire, significant improvement was recognized on the basis of the statements regarding the eye and lower back after BCA intake. (+info)
Psychological factors and visual fatigue in working with video display terminals.
OBJECTIVES: To examine the part played by psychological factors in complaints about visual health reported by banking officers who work at video display terminals (VDTs). METHODS: Out of a population of 385 bank workers, a group of 212 subjects without organic visual disturbances (as determined by ophthalmological examination) who share a work environment and job duties was selected. Three questionnaires were administered to these subjects: (a) the NIOSH job stress questionnaire; (b) a questionnaire investigating subjective discomfort related to environmental and lighting conditions of the workplace; (c) a questionnaire on the existence of oculovisual disturbances. Correlation and multiple regression analyses were performed to examine for the presence of predictors of asthenopia. RESULTS: Social support, group conflict, self esteem, work satisfaction, and underuse of skills were found to be predictors of visual complaints; social support played a part also as a moderating factor in the stress and strain model; this model accounted for 30% of the variance. Subjective environmental factors, although in some cases significantly correlated with asthenopia, were not found to be strong predictors of the symptoms. CONCLUSIONS: Some part of the complaints about visual health reported by VDT workers are likely indirect expressions of psychological discomfort related to working conditions. (+info)
Accommodative microfluctuation in asthenopia caused by accommodative spasm.
BACKGROUND: Although many patients complain of eye fatigue caused by accommodative spasm, there have been no reports of a good objective examination method to diagnose it. PURPOSE: The spectral power of the high frequency component of the accommodative microfluctuation (spectral power of HFC) differs according to the constrictive degree of the accommodation. In this paper, we expatiated upon our previously reported analyzing processes of the spectral power of HFC, and we investigated the relationship between normal subjects and subjects with asthenopia. METHOD: The accommodative microfluctuation were recorded when the subjects were looking at a stable target. The waves of the accommodative microfluctuation were analyzed by FFT. RESULTS: The spectral power of HFC for the distant target was 50-60 in the subjects with normal vision, but it was higher in the subjects with asthenopia. CONCLUSION: Our results suggested that the ciliary muscle was also actively working in asthenopia caused by accommodative spasm even if the patient was looking at a distant target. (+info)
Post-PRK muscular asthenopia and eccentric ablation.
OBJECTIVE: To investigate the relationship between muscular asthenopia post photorefractive keratectomy (PRK) and eccentric ablation. METHODS: 16 eyes of 8 myopia cases whose muscular asthenopia was corrected by subjectively accepted triangular prism after PRK with vision more than 0.8 were followed up for 6-14 months. On the basis of data provided by the pre-PRK, post-PRK and their difference corneal topography, we calculated the real corrected corneal diopter (D) with the Holladay formula and measured the ablating eccentricity (h) and its direction. According to the formula delta approximately Dh, the prism effective value (delta) caused by the eccentric ablation was computed and compared with objectively accepted triangular prism. RESULTS: The subjectively accepted prism was similar to values calculated from the formula. Their mean difference is 0.10 +/- 0.25. The direction of the subjectively accepted prism was in the direction of ablation deviation. CONCLUSIONS: Eccentric ablation was the chief cause of post-PRK muscular visual asthenopia. The triangular prism effective value from eccentric ablation may be estimated by the formula delta approximately Dh. We must pay attention to the diagnosis, treatment and prevention of post-PRK muscular asthenopia. (+info)
A novel in vitro model for screening and evaluation of anti-asthenopia drugs.
Patients suffering asthenopia are steadily increasing with an expanding use of visual display terminals such as computers. An attempt was made to develop an in vitro model for asthenopia. Ciliary muscle removed from eyeballs of a rabbit was stimulated with acethylcholine, resulting in contraction of the muscle. Repeated stimulations caused decreased contraction, which may be related to fatiguing of ciliary muscle and hence asthenopia. Treatment of the repeatedly stimulated muscle with cyanocobalamin restored contraction dose-dependently. Thus, the model developed in this study can be used to screen drug candidates for treating asthenopia. (+info)