Effects of Crocetin on the Pupillary Response during Accommodation Induced by Visual Display Terminal Work: A Randomized, Double-blind, Placebo-controlled, Crossover Trial / 日本補完代替医療学会誌

The purpose of this study was to examine the effects of crocetin on the pupillary response during accommodation induced by visual display terminal (VDT) work. This clinical study was conducted as a randomized, double-blind, placebo-controlled, crossover trial in healthy adult volunteers with subjective symptoms of eye fatigue. In this study, the pupillary response during accommodation was evaluated using pupil constriction ratio (PCR). PCR was measured before and after VDT work, after rest at baseline, and at each intervention period. Following analysis of variations in PCR, the variation in PCR after rest significantly increased in the crocetin group. According to the visual analog scale questionnaire, subjective symptoms of eye fatigue significantly improved. These results show that ingestion of crocetin for 4 weeks is effective in mitigating the pupillary response during accommodation associated with VDT work.

The Influence of Type of Computer and VDT Work on the Dryness of Eye

PURPOSE: This study was performed in order to discover the influence of the different types of computer and VDT work on the dryness of eyes. METHODS: Forty people without eye disease were included in this study. The frequency of blinking, BUT and width of palpebral fissure were measured after working on documents with desktop computers and laptop (notebook) computers and playing computer games at PC-room for 30 minutes each. RESULTS: The BUT value was 7.0+/-2.52 seconds after working on document with laptop computers and 5.7+/-1.86 seconds with desktop computers. Whereas the frequency of blinking was almost the same, the width of palpebral fissure was 6.6+/-0.95 mm in the former and 7.7+/-1.07 mm in the latter. After playing computer games at PC-room for 30 minutes, the BUT was as low as 4.6+/-1.61 seconds. The frequency of blinking was as low as 7.7+/-2.52 times/minute, and width of palpebral fissure as high as 9.2+/-1.24 mm. CONCLUSIONS: The highest value of palpebral fissure and the lowest value of BUT were obtained after playing computer games at PC room. These results indicate that the most severe dryness of eyes results from playing computer games at PC room and leads to eye fatigue easily. This was followed in the order of severe dryness by working on documents with desktop computers and laptop (notebook) computers. Therefore, proper rest during computer work, use of artificial tears and improved environment of the VDT working room are required.

The Influence of the Vertical Location of VDT Screen on the Ocular Dryness

The fatigue of eye is much caused by eye dryness during VDT work. We performed this study to find out whether eye dryness is reduced wit the computer screen which is placed lower than primary gaze during VDT work. Forty people without eye disease were selected. One VDT screen was placed 5degreesabove the primary gaze(5degreesup screen) and the other 25degreesbelow the primary gaze(25degreesdown screen). We measured the frequency of blinking and vertical palpebral fissure height, at rest and while they enjoyed an interesting computer game for 20 minutes. Tear film break-up time(BUT) was also measured at rest, during and immediately after computer game. At rest, the average frequency of blinking was 22.35+/-6.28/min and BUT was 10.20+/-2.63 seconds. During VDT work with 5degreesup screen, the measurements were significantly decreased to 7.48+/-3.43/min and 5.38+/-1.43/min, respectively. These, however, were improved with 25degreesdown screen showing 10.05+/-4.59/min and 7.00+/-1.55 second(p>0.01). The average vertical palpebral fissure height was 6.49+/-1.07mm at rest, and 9.49+/-1.26mm with 5degreesup screen. With 25degreesdown screen, this was 7.69+/-1.01mm and narrower than the measurement with 5degreesup screen(p>0.01). This study reveals that the visual fatigue from the ocular dryness will be improved with the computer screen placed 25degreeslower than primary gaze and laid adeqately back like in reading position.

A Study on the Relationship between Subjective symptoms and Psychological Symptoms on some VDT workers / 예방의학회지

The study subjects in this study are 295 workers who work on one electronics industry, and they were composed of 93 VDT and 202 non-VDT workers. This study was carried out to obtain the prevalence of subjective symptoms and to compare psychological symptom scores from SCL-90-R between VDT and non-VDT work groups. And to verify the relationship between VDT work related symptoms and psychological symptoms, the author compared scL-90-R T scores between symptom complaining and non-complaining groups. The results are summarized as follows: 1. Throughout the prevalence study of VDT work related symptoms according to VDT work state, the author could select the final 10 symptoms by sex; 'eye fatigue', 'foggy vision', 'neck discomfort or pain'. 'shoulder discomfort and pain', 'light headedness', 'dizziness', 'aene`, 'itching sensation on face', 'difficulty in concentration', 'memory disturbance' in males, and 'blurred vision`, 'foggy vision', 'neck discomfort or pain', 'shoulder discomfort and pain`, 'abdominal distention','indigestion', 'acne', 'pricking sensation on face', 'difficulty in concentration', 'memory disturbance` in females. 2. Throughout comparison of psychological symptom scores from SCL-90-R between VDT and non-VDT workers' except `interpersonal sensitivity` in female, Mean T score were higher in VDT workers, but not significantly different between the two groups. These results indicate that the relation between VDT work status and psychological symptoms are not strongly correlated. 3. Because of the nonspecific characteristics of VDT work related symptoms, from the 40 subjective symptoms, the author selected the final 10 symptoms by sex, especially correlated to VDT, and divided the study subjects into symptom complaining and non-complaining groups. The mean SCL-90-R T score between the two groups were compared. Except for the opthalmologic symptoms in females, the scores were significantly different between the two groups in all symptoms. And this indicates that the VDT work related symptoms strongly correlated with the present individual psychological conditions. 4. Due to understand that which of the 9 psychological symptom dimensions are strongly correlated with the subjective symptoms, the author excuted multiple logistic regression analysis, and the result were as follows; 'depression' and 'somatization', in male, and 'obsessive-compulsive' and 'somatization' in female.

The Effect of VDT Work on Vision and Eye Symptoms among Workers in a TV Manufacturing Plant / 예방의학회지

This study was conducted to evaluate the effect of VDT work on eyes and vision among workers in a TV manufacturing plant. The study subjects consisted of 264 screen workers and 74 non-screen workers who were less than 40 years old male and had no history of opthalmic diseases such as corneal opacities, trauma, keratitis, etc and whose visual acuity on pre-employment health examination by Han's test chart was 1.0 or above. The screen workers were divided into two groups by actual time for screen work in a day; Group 1, 60 workers, lesser than 4 hours a day and group 11, 204 workers, more than 4 hours a day. From July to October 1992 a questionnaire was administered to all the study subjects for the general charateristics and subjective eye symptoms after which the opthalmologic tests such as visual acuity, spherical equivalent, lacrimal function, ocular pressure, slit lamp test, fundoscopy were conducted by one opthalmologist. The proportion of workers whose present visual acuity was decreased more than 0. 15 in comparison with that on the pre-employment health examination by Han's test chart was 20.6% in Group Ii, 15.0% in Group I and 14.9% in non-screen workers. However, the differences in proportion were not statistically significant. The proportion of workers with decreased visual acuity was not associated with the age, working duration, use of magnifying glass and type of shift work (independent variables) in all of the three groups. However, screen workers working under poor illumination had a higher proportion of persons with decreased visual acuity than those working under adequate illumination (P<0.05). The proportion of workers whose near vision was decreased was 27.5% in Group II, 18.3% in Group I, and 28.4% in non-screen workers and these differences in proportion were not statistically significant. Changes of near vision were not associated with 4 independent variables in all of the three groups. Six out of sever-subjective eye symptoms except tearing were more common in Group I than in non-screen workers and more common in Group II than in Group I (P<0.01). Mean of the total scores for seven subjective symptoms of each worker (2 points for always, 1 point for sometimes, 0 point for never) was not significantly different between workers with decreased visual acuity and workers with no vision change. However, mean of the total scores for Group II was higher than those for the Group I and non-screen workers (P < 0. 01). Total eye symptom scores were significantly correlated with the grade of screen work, use of magnifying glass, and type of shift work. There was no independent variable which was correlated with the difference in visual acuity between the pre-employment health examination and the present state, the difference between far and near visions, lacrimal function, ocular pressure, and spherical equivalent. Multiple linear regression analysis for the subjective eye symptom scores revealed a positive linear relationship with actual time for screen work and shift work(P<0.01). In this study it was not observed that the VDT work decreased visual acuity but it induces subjective eye symptoms such as eye fatigue, blurred vision, ocular discomfort, etc. Maintenance of adequate illumination in the, work place and control of excessive VDT work are recommended to prevent such eye symptoms.

Industrial fatigue due to banking operations with VDT / 예방의학회지

In order to investigated industrial fatigue due to visual display terminal (VDT) work of banking operations, the questionnaires survey for subjective symptoms of fatigue was carried out on 470 bank clerks who had been engaged in VDT work for various length of work hours. The questionnaires comprised three groups of 10 items each, representing dullness and sleepiness (level of cerebral activation), difficulty in concentration (level of motivation) and bodily projection of fatigue. The results were as follows: 1. Of the 30 items of questionnaires, the highest percentage was accounted for by 'eye strain' (51.5%), followed by 'feel stiffness in the neck or the shoulders' (33.4%), 'feel a pain in the low back' (26.8%), 'whole body feels tired' (19.6%) and 'feel headache' (17.9%) in the order of sequence. 2. Ten average weighted score for the first group of questionnaire items (dullness and sleepiness) was the largest among three groups and was followed by the third group (bodily projection of fatigue) and the second item group (difficulty in concentration) in the order of sequence, suggesting the heavier mental stress of VDT work in banking operations rather than physical burden. 3. In terms of the age and sex of workers, work duration and VDT work percentage, the difference in average weighted score was noted only between sex, the score of female being larger than that of male. 4. The complaint rates of subjective symptoms showed close associations with the subjective optimums of room temperature, ventilation, illumination and noise level. 5. The significant correlation was showed between age, work duration and item of 'whole body feels tired', between VDT work percentage and items of 'eye strain' and 'feel stiffness in the neck or shoulders' and between all items of subjective symptoms.