VDT syndrome has been understood as the outocme of the computerized socio-economic cultures in this modern age. It affects many workers on larious visual functions as well as affecting some general health conditions including neurologic, circulatory, and musculosckeletal system. We conducted series of investigations to evaluate the influence of VDT work on the physiologic functions using objective ocular examinations on VDT workers with non-VDT workers as controls. Prolongation of near point decreased accommodation amplitude, myopic shift of refractive condition, and decreased amout of tear formation were significantly indicative in the VDT workers' group. The above functional disturbances can significahtly, deteriorate not only working effeciency but general physical condition if appropriate measures are not provided quickly. Therefore, it is firmly suggested that a comprehensive epidemiological study should be implemented aimed at ImprovIng working situations for VDT workers.
Asthenopia ; Epidemiologic Studies ; Tears

PURPOSE: To evaluate stability and effects of photochromic lenses in light-sensitive patients. METHODS: Analyzing 65 patients, this research employed a standardized survey, fundus examination, and slit-lamp biomicroscopy to evaluate the changes in photophobia, tears, asthenopia, and the deterioration of outdoor visual acuity after wearing photochromic lenses for one month. Measurement of visual acuity was performed outdoors at noon on a bright day using Dr. Hahn's standard test chart for 3 m. RESULTS: Photochromic lenses, considerably decreased photophobia, tears, and asthenopia. The "normal" visual acuity of 38 patients was established without photochromic lenses. Re-examination after the lenses had been worn for a specified period of time showed that 29 subjects could discern at least one line higher than their "normal" acuity. CONCLUSIONS: Photochromic lenses reduced photophobia and the disabling effect of bright light such that comfort was increased. Not only did the lenses improve vision, they also enhanced the overall quality of vision.
Asthenopia ; Humans ; Photophobia ; Visual Acuity

PURPOSE: To evaluate the benefit of colored filters in Meares-Irlen Syndrome patients with reading difficulties. METHODS: Twenty-five patients were selected through a brief questionnaire aimed to determine symptoms of eyestrain or visual distortion after thorough eye examinations. The cutoff value of the questionnaire was 2.13. The rates of Korean reading and writing were measured using the RWSM (Reading Writing Speed Meter) test with and without the use of colored filters. Two months after wearing the individually prescribed colored filters, a questionnaire on the patient's subjective satisfaction with the colored filters were completed and evaluated. RESULTS: The blue (n = 8, 32%) and gray (n = 4, 16%) colors were the most frequently selected filters. The mean score of the questionnaire on reading difficulties was 2.72. The mean reading rate improved from 82.72 wpm (words per minute) to 101.84 wpm with the colored filters, a statistically significant change (p = 0.019). The mean writing rate did not improve. The overall satisfaction score with the colored lenses was 3.6, with the highest score given to ease of reading (4.08) and the lowest to writing (2.92). CONCLUSIONS: In cases of reading difficulty, colored filters were effective for alleviating visual symptoms and improving reading speed. It is important to achieve an adequate understanding of the specific symptoms of Meares-Irlen Syndrome and to perform a thorough eye examination to differentiate this from other ocular disorders.
Asthenopia ; Dyslexia ; Eye ; Humans ; Surveys and Questionnaires ; Writing

PURPOSE: The purpose of this study was to identify sleep patterns, alertness, and fatigue of shift nurses according to circadian types. METHODS: The researchers' enrolled 17 nurses doing shift work in a tertiary hospital. To evaluate circadian types, a morningness-eveningness questionnaire (MEQ) was administered. Sleep patterns were examined using an actigraph for 14 days. To assess alertness and fatigue, Visual Analogue Scale (VAS) was used. The data were analyzed using ANOVA and Kruskal-Wallis test with a SPSS 21.0 program. RESULTS: The researchers found that 17.6% of participants reported morning type, 47.1% neither type, and 35.3% evening type. Mean total sleep time (TST) was 6.8 h, mean sleep efficacy was 82%, level of alertness was 6.54, and level of fatigue was 5.49, regardless of the type of shift work. Evening type nurses had higher variation in TST and alertness, according to the shift patterns than other circadian type nurses. Evening type nurses also had higher fatigue levels than other circadian type nurses. CONCLUSION: Sleep, alertness, and fatigue were related with circadian types. These results suggest that circadian rhythm management in shift work nurses, particularly in evening type nurses is urgently needed to improve sleep patterns, alertness, and to decrease the level of fatigue.
Asthenopia ; Circadian Rhythm ; Fatigue* ; Tertiary Care Centers

In 54 cases with heterophoria, the effects of the tranquilizers were studied. The minimum doses of two kinds of tranquilizers i.e., phenothiazine derivative (chlorpromazine) and benzodiazepine derivative (oxazepam) were given for 3 days. The results were as follows: 1. In 18 cases (43%) of the 30 cases who complained asthenopia, the symptom was relieved to some extent. The improvement of the symptom occurred with decrease in the Jateral phoria in 13 cases, and with increase in fusional amplitude in 13 cases. 2, There were no changes in the lateral phoria in 31 cases (59%) at distance, but at near, in 27 cases (52%) there was decrease in the lateral phoria. The amount of the increment or decrement in prism diopters was somewhat larger at near than at distance, and also somewhat larger in cases, in which the initial lateral phoria before medication is high, than in the cases with low initial lateral phoria. 3, There were no changes in the fusional amplitude in 24 cases (46%) at distance, but at near, in 28 cases (55 %) there was the increase in fusional amplitude. The changes in the amount of the increment or decrement in the fusional al1}plitude were similar to that of the changes in the amount in lateral phoria. 4, There were no remarkable changes in vertical phorias. 5. In exophoria there were no remarkable differences between subjects given chlorpromazine and those gIven oxazepam.
Asthenopia ; Benzodiazepines ; Chlorpromazine ; Exotropia ; Oxazepam ; Strabismus

Authors performed a comparison study of eye fatigue after full 60 minutes continuous reading the prepared daily newspapers which were differently arranged in various writings vertical style or horizontal style, under the illuminations (50, 200 and 1000 Lux)and two kinds of light source(fluorescent lamp and glow lamp), by the flicker fusion test. Healthy persons(8 for young ages: 20~29 yr. old, and 8 for old, ages: 50~59 yr. old) were carefully selected for the purpose of this study. Results are as follows: 1. There is no significant difference in flicker values between vertical and horizontal writings. 2. Flicker values after one hour continuous reading under the illuminlition of 50 and 1000 Lux were significantly decreased in comparison to 200 Lux illumination in old age. (P.<0.05). 3. Flicker values were significantly decreased after 50 minutes continuous reading the newspapers in all conditions, such as style of writing, light sources and illuminations.(p<0.05). 4. Different light sources such as fluorescent lamp and glow lamp also showed no significant differences in inducing eye fatigue. 5. There is no significant difference in inducing eye fatigue between young(20~29 yr. old) and old(50~59 yr. old) age group.
Asthenopia* ; Flicker Fusion ; Humans ; Lighting ; Periodicals* ; Writing

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.
Asthenopia ; Blinking ; Eye Diseases ; Fatigue ; Tears ; Video Games

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.
Asthenopia ; Blinking ; Eye Diseases ; Ophthalmic Solutions ; Video Games

The ocular symptoms of visual display terminal (VDT) syndrome are caused by asthenopia, electromagnetic waves, and eye fatigue. To find out what cause make the fatigue of eye during VDT work, we measured frequency of blinking and height of palpebral fissure at near, reading a book, and during VDT work. Tear film break-up time(BUT) was measured immediately after the VDT work and during reading a book. The frequency of blinking during VDT work and book reading decreased significantly comparing with the one at rest (p<0.01). The average frequency of blinking is 20.52 +/- 5.89/min at rest, 8.29 +/- 4.15/min at VDT work, and 10.31 +/- 5.48/min at reading. The BUT measured immediately after VDT work decreased much more than in the resting state (p<0.01). The average BUT was 11.52 +/- 3.41sec at rest and 6.18 +/- 2.65sec immediately after VDT work. The height of palpebral fissure during VDT work increased significantly comparing with the value at rest (p<0.01). The average height of palpebral fissure was 7.39 +/- 0.78mm at rest and 8.83 +/- 0.75mm during VDT work. This study reveals the fatigue of eye during VDT work was induced by the dryness of eye resulted from the increased evaporation due to the decrement in the frequency of blinking and the widening of palpebral fissure. To prevent the fatigue of eye caused by dryness during VDT work, it is important for VDT workers to intend to blink frequently, place VDT lower than eye level to reduce the height of palpebral fissure, humidify the room adequately, put artificial eye tear in eye frequently, and take a rest after 20 mimutes work at least.
Asthenopia ; Blinking ; Electromagnetic Radiation ; Eye, Artificial ; Fatigue ; Tears

Regular astigmatism is the condition in which the refractive power changes gradually from one meridian to the next by uniform increments, and the two principal meridians are placed at right angles to each other. Astigmatism is one of the most important cause that is concerned with visual disturbance. When there are no serious deterioration of the visual acuity and no symptoms of asthenopia astigmatic errors do not require correction. But if either of those two conditions is present, the errors should be corrected by lenses. A false position of the cylinder axis in a corrected lens creates a new astigmatism. The larger the error in the position of the correcting cylinder, the larger is the amount of the resultant astigmatic error. The axis of new astigmatism does not coincide with the axis of the cylinder lens nor the original astigmatism of the eye. When the amount of astigmatism is large, the axial error may impair the visual acuity. The two kinds of errors in position of axis that caused respectively a blur of letters or visual acuity of 20/30 on Snellen chart by rotating the trial cylinder in the trial frame, and the reduced amount of cylinder power that caused blur of letters on Snellen chart were studied in 210 eyes with astigmatism of less than 2 diopters. The results were as follow: 1. When the patients recognized blurring by rotating the trial cylinder, the average error in position of axis was respectively 18 degrees +/- 0.42 in cylinder power of 0.25D - 0.50D, 11 degrees +/- 0.29 in 0.75D - 1.00D, 9 degrees +/- 0.29 in 1.25D - 1.50D and 4 degrees +/- 0.24 in 1.75D - 2.00D. 2. At the visual acuity of 20/30 by rotating the trial cylinder, the average error in position of axis was respectively 70 degrees +/- 0.22 in cylinder power of 0.25D - 0.50D, 29D +/- 0.79 in 0.75D - 1.0DD, 17 degrees +/- 0.37 in 1.25D - 1.50D and go +/- 0.36 in 1.75D - 2.00D. 3. In astigmatism of less than 1.50D, the error in position of axis in against-the-rule astigmatism was significantly smaller than that in with-the-rule or that in oblique when the patients, recognized blurring by rotating the trial cylinder. 4. In astigmatism of less than 1.50D, the error in position of axis in against-the rule astigmatism was significantly smaller than that in with-the-rule or that in oblique at the visual acuity of 20/30 by rotating the trial cylinder. 5. In astigmatism of less than 1.50D, the larger the amount of spherical lens, the larger was the error in position of axis when the patients recognized blurring by rotating the trial cylinder. 6. In astigmatism of less than 1.50D, the larger the amount of spherical lens, the larger was the error in position of axis at the visual acuity of 20/30 by rotating the trial cylinder. 7. When the patients recognized blurring by reducing cylinder power, the reduced cylinder power was respectively 0.19D +/- 0.01 in cylinder power of 0.25D - 0.50D, 0.29D +/- 0.02 in 0.75D - 1.00D, 0.35D +/- 0. 02 in 1.25D - 1.50D and 0.38D +/- 0.01 in 1.75 - 2.00D. 8. In cylinder power of 1.25D - 1.50D, the reduced amount of cylinder power that caused blurring was significantly smaller in against-the-rule astigmatism than in with-the-rule.
Asthenopia ; Astigmatism* ; Axis, Cervical Vertebra* ; Humans ; Meridians ; Visual Acuity