Visual display terminal syndrome and its associated factors among university students during the COVID-19 pandemic.

BACKGROUND: Ever since the start of the coronavirus disease 2019 (COVID-19) pandemic, students have been spending an increasingly longer time staring at electrical devices to take online courses. OBJECTIVE: This study aimed to investigate the effect of the virtual class environment on eye and musculoskeletal problems in university students during the COVID-19 pandemic. METHODS: A total of 365 university students were enrolled in this study. They completed an online survey to examine the effects of online learning on eye and musculoskeletal health during the COVID-19 pandemic. The questionnaires consisted of four sections: demographic and general information, environmental and work factors, device-related factors, and visual display terminal syndrome (VDTS). RESULTS: Participants have been taking online classes of 14.5 hours per week during the COVID-19 pandemic. They reported the mean daily usage of digital devices of 4.8±2.2 hours before the pandemic but this increased to 8.1±2.9 during the pandemic. Eye fatigue and neck, shoulder, and back pain have also been reported. The mean VDTS score was significantly influenced by gender, obesity, daily exercise, regular breaks, wear of blue light-blocking glasses, daily hours of electronic device use, and illumination of room. CONCLUSION: The results of this study showed that university students taking online classes suffered more from VDTS, especially in eye fatigue and neck, lower back, and shoulder pain during COVID-19 pandemic than prior. This study suggests that it is necessary to take breaks in online classes and regularly provide appropriate eye exercise and physical activity to prevent VDTS.

Computer vision syndrome and associated factors in university students and teachers in Nampula, Mozambique.

BACKGROUND: Computer Vision Syndrome (CVS) is a complex of eye and visual problems that arise while using a computer or other Video Display Terminal (DVT). With the advent of the COVID-19 pandemic, the use of these DVTs has become indispensable in the lives of students and teachers. This study aims to identify the prevalence of CVS and associated factors in students and teachers at Lúrio University, in Nampula, during the pandemic period. METHODS: This is a cross-sectional study, carried out between November 2020 and March 2021. The validated CVS questionnaire (CVS-Q) and another semi-structured questionnaire on ergonomic risk factors were applied. Odds ratios (OR) and adjusted odds ratios (aOR) were calculated to measure the association between CVS and computer use conditions. RESULTS: The prevalence of CVS was 76.6%, and the female gender, age ≤ 20 years, levels I, II, III of course, lack of knowledge about ergonomics, use the computer to study, use more than 6 hours daily, absence of anti-reflex treatment, use of other devices and sitting in an inappropriate chair were risk factors for the occurrence of CVS, while being a teacher was a protective factor. CONCLUSION: The prevalence of CVS found in this study was high, due to several factors, especially not using ergonomic principles when using computers and other DVTs. There is a need to adopt intervention strategies focused on the most vulnerable groups such as women, age group ≤20 years and students, especially at the first year level, right after entering the University.

Association between time spent on smartphones and digital eye strain: A 1-year prospective observational study among Hong Kong children and adolescents.

Prolonged electronic screen use can cause digital eye strain. It can be difficult to rectify due to increasing smartphone reliance, potentially leading to serious public health problems. To investigate the association between time spent on smartphones and digital eye strain (DES) among Hong Kong Chinese school-aged children. Of a total of 1,508 students (748 males, 49.6%) from 8 to 14 years old (mean age = 10.91 years, SD = 2.01) who provided valid data on DES, the 1,298 (86%) who completed the DES questionnaire at 1-year follow-up were included in the analysis. DES was measured using a 10-item scale, and the sum of the 10 dichotomised scores was used as the DES total score. The most commonly reported symptoms were eye fatigue (n = 804, 53.3%), blurred vision (changing from reading to distance viewing) (n = 586, 38.9%), and irritated or burning eyes (n = 516, 34.2%). The DES total scores at baseline and 1-year follow-up were 2.91 (SD = 2.90) and 3.20 (SD = 3.19), respectively. Linear regression controlling for demographic and socio-economic confounders showed that participants with baseline smartphone usage of 241 + min/d had a significantly higher baseline total DES score than those with baseline smartphone usage of 0-60 min/d (2.44 vs 3.21, P < 0.001), and participants with baseline smartphone usage of 181-240 min/d had a significantly higher 1-year follow-up total DES score than those with baseline smartphone usage of 0-60 min/d (2.80 vs 3.50, P = 0.003).

Improving Visual Comfort during Computer Gaming with Preservative-Free Hyaluronic Acid Artificial Tears Added to Ergophthalmological Measures.

Digital asthenopia (DA) or Computer Vision Syndrome can occur after prolonged use of digital devices and is usually managed with ergophthalmological measures and the use of artificial tears. This prospective, controlled study evaluated the use of hyaluronic acid artificial tears on the signs and symptoms of DA in participants of a videogame convention. Subjects (n = 56) were randomized into a control group (CG, n = 26), which followed ergophthalmological measures, and a study group (SG, n = 30), which followed ergophthalmological measures and instilled 1 drop of artificial tears with hyaluronic acid 0.15% four times a day. Subjects were evaluated before and after playing for three consecutive days for eye dryness (SPEED questionnaire), conjunctival hyperemia, corneal fluorescein staining, conjunctival lissamine green staining, tear breakup time, Schirmer I test, near convergence and accommodation, and using questionnaires for DA symptoms. After 3 days of intense videogaming, the SPEED score of CG increased significantly (p = 0.0320), while for the SG it was unchanged. Similarly, the CG presented significant increases in ocular fatigue (p = 0.0173) and dryness (p = 0.0463), while these parameters decreased significantly in the SG (p = 0.0149 and p = 0.00427, respectively). This study confirms the protective effect of hyaluronic acid artificial tears against DA symptoms associated with prolonged visual display terminal use.

Effects of the concentration level, eye fatigue and coffee consumption on the performance of a BCI system based on visual ERP-P300.

BACKGROUND: A widely used paradigm for Brain-Computer Interfaces (BCI) is based on detecting P300 Event-Related Potentials (ERPs) in response to stimulation and concentration tasks. An open challenge corresponds to maximizing the performance of a BCI by considering artifacts arising from the user's cognitive and physical conditions during task execution. NEW METHOD: In this study, an analysis of the performance of a visual BCI-P300 system was performed under the metrics of Sensitivity (Sen), Specificity (Spe), Accuracy (Acc), and Area-Under the ROC Curve (AUC), considering the main reported factors affecting the neurophysiological behavior of the P300 signal: Concentration Level, Eye Fatigue, and Coffee Consumption. COMPARISON WITH EXISTING METHODS: We compared the performance of three P300 signal detection methods (MA-LDA, CCA-RLR, and MA+CCA-RLR) using a public database (GigaScience) in different groups. Data were segmented according to three factors of interest: high and low levels of concentration, high and low eye fatigue, and coffee consumption at different times. RESULTS: The results showed a significant improvement between 3% and 6% for the metrics evaluated for identifying the P300 signal in relation to concentration levels and coffee consumption. CONCLUSION: P300 signal can be influenced by physical and mental factors during the execution of ERPs evocation tasks, which could be controlled to maximize the interface's capacity to detect the individual's intention.

Effects of an ergonomic intervention program based on the PRECEDE-PROCEED model for reducing work-related health problems and exposure risks among emergency medical dispatchers.

OBJECTIVE: To evaluate the effectiveness of an ergonomic intervention program based on the PRECEDE-PROCEED model in terms of improving exposure risks and work-related health problems in emergency medical dispatchers. METHODS: This quasi-experimental study used an interrupted time series design. Participants were 55 employees working in an Emergency Medical Communications Center in Iran. The intervention program was based on the PRECEDE-PROCEED model and included five face-to-face training sessions and installing auxiliary equipment according to best ergonomic principles. Direct observations of the emergency medical dispatchers' working postures using the Rapid Office Strain Assessment and a survey which included a modified Nordic Questionnaire, Work Ability Score, Visual Fatigue Questionnaire, and a Behavioral Factors Questionnaire were used at three time points: baseline, 1 month post-intervention, and 3 months post-intervention. RESULTS: The modified Nordic Questionnaire showed significant reductions in pain intensity scores for neck, lower back, knee and ankle after the ergonomic intervention program. In addition, there were considerable post-training improvements in behavioral factors (knowledge and enabling factors) and working postures. No significant changes were observed in Work Ability Scores, or visual symptoms. CONCLUSIONS: An ergonomic intervention program based on a systematic framework such as the PRECEDE-PROCEED model and on-site interventions can be effective in improving and enhancing the working conditions of emergency medical dispatchers. Therefore, it is suggested that ergonomic interventions be implemented based on standard and valid behavioral change models such as PRECEDE-PROCEED model in other work environments in which musculoskeletal pain and digital eye strain are common.

Do Head-Mounted Augmented Reality Devices Affect Muscle Activity and Eye Strain of Utility Workers Who Do Procedural Work? Studies of Operators and Manhole Workers.

OBJECTIVE: The objective was to determine the effect of two head-mounted display (HMD) augmented reality (AR) devices on muscle activity and eye strain of electric utility workers. The AR devices were the Microsoft HoloLens and RealWear HMT-1. BACKGROUND: The HoloLens is an optical see-through device. The HMT-1 has a small display that is mounted to the side of one eye of the user. METHOD: Twelve power plant operators and 13 manhole workers conducted their normal procedural tasks on-site in three conditions: HoloLens, HMT-1, and "No AR" (regular method). Duration of test trials ranged up to 30 s for operators and up to 10 min for manhole workers. Mean and peak values of surface electromyographic (sEMG) signals from eight neck muscles were measured. A small eye camera measured blink rate of the right eye. RESULTS: In general, there were no differences in sEMG activity between the AR and "No AR" conditions for both groups of workers. For the manhole workers, the HoloLens blink rate was 8 to 11 blinks per min lower than the HMT-1 in two tasks and 6.5 fewer than "No AR" in one task. Subjective assessment of the two AR devices did not vary in general. CONCLUSION: The decrease in blink rate with the HoloLens may expose utility manhole workers to risk of eye strain or dry-eye syndrome. APPLICATION: HMD AR devices should be tested thoroughly with respect to risk of eye strain before deployment by manhole workers for long-duration procedural work.

Short tear film breakup time-type of dry eye in India.

PURPOSE: The aim of this study was to describe the clinical characteristics and risk factors of short tear film break-up time (TBUT) type of dry eye disease and compare it with other types of dry eye diseases. METHODS: This cross-sectional study included 570 patients (≥ 20 years) from the outpatient department using systematic random sampling. RESULTS: The age-adjusted prevalence of short TBUT type of dry eye disease was 5.4% (95% confidence interval: 3.2-6.8%). There was no difference (P > 0.05) between the total and subscale scores of the Ocular Surface Disease Index® questionnaire between patients with short TBUT and those with aqueous tear deficiency. Both these groups differed significantly (P < 0.05) in the findings of TBUT, Schirmer I test, and Lissamine green staining score. The common symptoms in patients with short TBUT type of dry eye disease were eye fatigue (25.4%), heaviness in the eye (19.7%), and an uncomfortable sensation (14.1%). The symptoms in the aqueous tear deficiency group were light sensitivity (28.2%), dryness (19.2%), burning (13.0%), foreign body sensation (12.8%), and blurring of vision (14.1%). The risk factors associated with short TBUT type of dry eye disease were the presence of meibomian gland dysfunction (odds ratio: 3.759 [95% confidence interval: 2.135-6.618], P < 0.0001) and female sex [odds ratio: 1.954 (95% confidence interval: 1.042-3.667), P = 0.037]. CONCLUSION: Patients with short TBUT type of dry eye disease have symptom severity similar to aqueous tear-deficient dry eyes, but the pattern is different. The finding of this type of dry eye disease in India indicates its global presence, and ophthalmologists should consider it in their differential diagnoses.

Evaluation of Eye-Pain Severity between Dry-Eye Subtypes.

The aim of this study was to assess eye pain between dry eye (DE) subtypes using questionnaires and the PainVision® (Osachi) apparatus. This study involved 52 eyes of 52 DE patients with eye pain (43 females and 9 males; mean age: 64.2 ± 13.2 (mean ± SD) years) who were classified into three DE subtypes (aqueous deficient DE (ADDE); decreased wettability DE (DWDE); and increased evaporation DE (IEDE)) based on fluorescein breakup pattern. In all subjects, severity of eye pain was evaluated using PainVision®, the DE-symptom-questionnaire visual analog scale (DSQ-VAS), and the Short-Form McGill Pain Questionnaire 2 (SF-MPQ-2). The severity of eye pain was compared between the three DE subtypes. PainVision® findings revealed greater severity of eye pain in ADDE and DWDE than in IEDE (p < 0.05, respectively), despite no difference being found in each questionnaire. A significant correlation was found between eye pain in DSQ-VAS and continuous pain, intermittent pain, neuropathic pain, and total pain in SF-MPQ-2 (R = 0.50, 0.49, 0.47, and 0.56, respectively) (all: p < 0.001). Greater severity of eye pain was found in ADDE and DWDE than in IEDE, and PainVision® was found useful for the objective assessment of eye pain.

Ocular symptoms associated with digital device use in contact lens and non-contact lens groups.

PURPOSE: Previous reports indicate that "eye fatigue" occurs in roughly 60 % of the adult population using digital devices and may negatively impact quality of life. However, the construct of eye fatigue remains poorly understood. The goal of this study was to quantify the relationship among symptoms most frequently associated with eye fatigue in those using digital devices. METHODS: Six hundred and two soft contact lens (SCL) wearers and 127 non-contact lens (non-CL) wearers who reported using digital devices at least 4 hours per day completed a questionnaire assessing the frequency and severity of ten symptoms commonly associated with digital device-related eye fatigue. Subjective ratings were made separately for each symptom using unipolar, five-point Likert scales. RESULTS: From the initial pool of respondents, 89 % of the SCL wearers reported experiencing eye fatigue more than once per month, while over 60 % reported more than once per week. Notably, eye fatigue frequency did not differ between the soft contact and non-contact lens groups. Although eye strain/pain, dryness, and tired eyes were the most frequently endorsed symptoms by both groups, only dryness and eye irritation were significant factors that discriminated the SCL from the non-CL wearers on the basis of frequency and severity. Principal component analysis indicated that eye strain/pain, soreness, tired eyes, and headaches may comprise a "primary sensations" factor, whereas burning, eye irritation, tearing and dryness comprise a "secondary or surface sensations" factor, and blurred/double vision and words move/float comprise a "visual sensations" factor. Confirmatory factor analysis (CFA) of frequency and severity ratings for SCL wearers yielded excellent fits (RMSEA = 0.046 and 0.050, respectively) with construct reliabilities ranging from 0.729 to 0.824. CONCLUSION: Frequent and severe eye fatigue is highly prevalent among both soft contact lens and non-contact lens wearers. Those utilizing SCL do not experience symptoms at higher frequency or severity. Key descriptors of digital eye fatigue have been identified and may then be used to help identify and evaluate specific causative, palliative, or ameliorating factors.

A Machine Learning Based Dose Prediction of Lutein Supplements for Individuals With Eye Fatigue.

Purpose: Nutritional intervention was always implemented based on "one-size-fits-all" recommendation instead of personalized strategy. We aimed to develop a machine learning based model to predict the optimal dose of a botanical combination of lutein ester, zeaxanthin, extracts of black currant, chrysanthemum, and goji berry for individuals with eye fatigue. Methods: 504 features, including demographic, anthropometrics, eye-related indexes, blood biomarkers, and dietary habits, were collected at baseline from 303 subjects in a randomized controlled trial. An aggregated score of visual health (VHS) was developed from total score of eye fatigue symptoms, visuognosis persistence, macular pigment optical density, and Schirmer test to represent an overall eye fatigue level. VHS at 45 days after intervention was predicted by XGBoost algorithm using all features at baseline to show the eye fatigue improvement. Optimal dose of the combination was chosen based on the predicted VHS. Results: After feature selection and parameter optimization, a model was trained and optimized with a Pearson's correlation coefficient of 0.649, 0.638, and 0.685 in training, test and validation set, respectively. After removing the features collected by invasive blood test and costly optical coherence tomography, the model remained good performance. Among 58 subjects in test and validation sets, 39 should take the highest dose as the optimal option, 17 might take a lower dose, while 2 could not benefit from the combination. Conclusion: We applied XGBoost algorithm to develop a model which could predict optimized dose of the combination to provide personalized nutrition solution for individuals with eye fatigue.

Lactobacillus paracasei KW3110 Suppresses Inflammatory Stress-Induced Premature Cellular Senescence of Human Retinal Pigment Epithelium Cells and Reduces Ocular Disorders in Healthy Humans.

Lactobacillus paracasei KW3110 (KW3110) has anti-inflammatory effects and mitigates retinal pigment epithelium (RPE) cell damage caused by blue-light exposure. We investigated whether KW3110 suppresses chronic inflammatory stress-induced RPE cell damage by modulating immune cell activity and whether it improves ocular disorders in healthy humans. First, we showed that KW3110 treatment of mouse macrophages (J774A.1) produced significantly higher levels of interleukin-10 as compared with other lactic acid bacterium strains (all p < 0.01). Transferring supernatant from KW3110- and E. coli 0111:B4 strain and adenosine 5'-triphosphate (LPS/ATP)-stimulated J774A.1 cells to human retinal pigment epithelium (ARPE-19) cells suppressed senescence-associated phenotypes, including proliferation arrest, abnormal appearance, cell cycle arrest, and upregulation of cytokines, and also suppressed expression of tight junction molecule claudin-1. A randomized, double-blind, placebo-controlled parallel-group study of healthy subjects (n = 88; 35 to below 50 years) ingesting placebo or KW3110-containing supplements for 8 weeks showed that changes in critical flicker frequency, an indicator of eye fatigue, from the week-0 value were significantly larger in the KW3110 group at weeks 4 (p = 0.040) and 8 (p = 0.036). These results suggest that KW3110 protects ARPE-19 cells against premature senescence and aberrant expression of tight junction molecules caused by chronic inflammatory stress, and may improve chronic eye disorders including eye fatigue.

A novel botanical formula improves eye fatigue and dry eye: a randomized, double-blind, placebo-controlled study.

BACKGROUND: With the frequent use of video display units, eye fatigue is becoming more common globally. An alternative nutritional strategy is needed to prevent the aggravation of eye fatigue symptoms. OBJECTIVES: The objective was to evaluate the protective effect of a novel botanical combination of lutein ester, zeaxanthin, and extracts of blackcurrant, chrysanthemum, and goji berry on adults with eye fatigue in a randomized, double-blind, placebo-controlled clinical trial. METHODS: We randomly allocated 360 participants into 4 groups to receive placebo and 3 doses of our formula (chewable tablets, containing 6 mg, 10 mg, or 14 mg of lutein) once daily for 90 d. Each participant had 3 visits at baseline (V1), 45 d (V2), and 90 d (V3) during the study. RESULTS: Intervention with the formula improved individual scores of eye fatigue symptoms, including eye soreness, blurred vision, dry eye, foreign body sensation, and tearing. Compared with placebo, the formula at all 3 doses significantly decreased the total score of eye fatigue symptoms and increased the visuognosis persistence time at both V2 and V3. According to the Schirmer test, both 10-mg and 14-mg lutein formula groups had improved tear secretion at V3 compared with the placebo. The keratography results indicated that the first tear break-up time, average tear break-up time, and tear meniscus height were significantly increased after formula intervention. The formula at all 3 doses significantly increased the macular pigment optical density at V2 and V3 compared with the placebo, whereas optical coherence tomography showed no significant difference in retinal thickness and retinal volume across all groups at both visits. CONCLUSIONS: Our botanical formula improves eye fatigue, dry eye, and macular function without changing the retinal structure, and thus it could serve as an effective nutritional strategy in improving eye fatigue without causing serious side effects.Clinical Trial Registry: chictr.org.cn (ChiCTR1800018987).

Reduction of visual acuity decreases capacity to evaluate radiographic image quality.

INTRODUCTION: To determine the impact of reduced visual acuity on the evaluation of a test object and appendicular radiographs. METHODS: Visual acuity was reduced by two different magnitudes using simulation glasses and compared to normal vision (no glasses). During phase one phantom images were produced for the purpose of counting objects by 13 observers and on phase 2 image appraisal of anatomical structures was performed on anonymized radiographic images by 7 observers. The monitors were calibrated (SMPTE RP133 test pattern) and the room lighting was maintained at 7 ± 1 lux. Image display and data on grading were managed using ViewDEX (v.2.0) and the area under the visual grading characteristic (AUCVGC) was calculated using VGC Analyzer (v1.0.2). Inferential statistics were calculated using SPSS. RESULTS: For the evaluation of appendicular radiographs the total interpretation time was longer when visual acuity was reduced with 2 pairs of simulation glasses (15.4 versus 8.9 min). Visual grading analysis showed that observers can lose the ability to detect anatomical and contrast differences when they have a simulated visual acuity reduction, being more challenging to differentiate low contrast details. No simulation glasses, compared to 1 pair gives an AUCVGC of 0.302 (0.280, 0.333), that decreases to 0.197 (0.175, 0.223) when using 2 pairs of glasses. CONCLUSIONS: Reduced visual acuity has a significant negative impact on the evaluation of test objects and clinical images. Further work is required to test the impact of reduced visual acuity on visual search, technical evaluation of a wider range of images as well as pathology detection/characterization performance. IMPLICATIONS FOR PRACTICE: It seems that visual performance needs to be considered to reduce the risks associated with incomplete or incorrect diagnosis. If employers or professional bodies were to introduce regular eye tests into health screening it may reduce the risk of misinterpretation as a result of poor vision.

Effect of Yoga Ocular Exercises on Eye Fatigue.

BACKGROUND: Comfortable working at near and intermediate tasks depend on the efficiency as well as coordination of accommodation and vergence systems. At present, the need for near and intermediate visual tasks has been dramatically increased, requiring prolonged computer- and gazette-related works. It demands excessive working of the extraocular and ciliary muscles. It may cause eye fatigue and other associated asthenopic symptoms. Globally, eye fatigue is one of the most commonly reported conditions in nonpresbyopic population with asthenopic symptoms. It is necessary to get relief from eye fatigue for better near and intermediate tasks. MATERIALS AND METHODS: Thirty-two undergraduate optometry students who were symptomatic based on a validated eye fatigue questionnaire were included after a baseline comprehensive eye examination. Based on the eye fatigue symptoms score, they were equally assigned to a control group and an exercise group with sixteen participants in each. The exercise group performed yoga ocular exercises for up to 6 weeks after which the eye fatigue symptoms were reassessed in both groups. RESULTS: In the exercise group, there was a statistically significant reduction in eye fatigue scores (P = 0.003), whereas the eye fatigue scores showed significant increment in the control group after 6 weeks (P = 0.044). CONCLUSIONS: Yoga ocular exercises reduce the eye fatigue symptoms score by increasing the efficiency of extraocular muscles. Hence, it could be considered as a therapeutic and nonpharmacologic intervention for reducing the eye fatigue and associated asthenopic symptoms.

Insufficient accommodation during binocular near viewing in eyes with intermittent exotropia.

PURPOSE: To investigate the changes in spherical equivalent and pupil response during near viewing in patients with intermittent exotropia (IXT) who have complaints of blurred vision or asthenopia from near viewing in daily life using a novel binocular wavefront aberrometer. STUDY DESIGN: A cross-sectional study. METHODS: Ten IXT patients and ten healthy subjects wearing full-correction lenses at far sight (5 m) were instructed to fixate on a near target at 67 cm, which was then moved to 40 cm three times. Serial changes in the spherical equivalent (SE) refractive error (SE) were measured during this task using a laboratory-made open-field binocular Hartmann-Shack wavefront aberrometer and compared between patients and healthy subjects. In the IXT patients, regression analysis was performed between ∆SE and exodeviation angles, as measured by an alternate prism and cover test. Pupil-diameter and pupil-constriction ratios were also compared between patients and healthy subjects, and the correlation of constriction ratio with ∆SE was calculated for both groups. RESULTS: Compared to healthy subjects, IXT patients demonstrated significantly lower ∆SE of convergence (mean ± SD, 0.91 ± 0.26 D vs. 1.15 ± 0.19 D; P < 0.05) and divergence (0.93 ± 0.28 D vs. 1.16 ± 0.20 D; P < 0.05). Angle of exotropia was negatively correlated with ∆SE during far-sight and near-sight convergence and divergence (P < 0.05). Pupil-constriction ratio was also reduced in patients compared to healthy subjects (6.67% ± 3.31% vs. 11.9% ± 5.96%; P<0.05). Pupil-constriction ratio was positively correlated with ∆SE during convergence in both groups (P < 0.05). CONCLUSION: Insufficient accommodation and pupil constriction during near viewing were observed in patients with IXT who had complaints of blurred vision or asthenopia from near viewing. These conditions might contribute to symptoms, such as fatigue, eye strain and impaired visual performance.

Assessment of eye fatigue caused by head-mounted displays using eye-tracking.

BACKGROUND: Head-mounted displays (HMDs) and virtual reality (VR) have been frequently used in recent years, and a user's experience and computation efficiency could be assessed by mounting eye-trackers. However, in addition to visually induced motion sickness (VIMS), eye fatigue has increasingly emerged during and after the viewing experience, highlighting the necessity of quantitatively assessment of the detrimental effects. As no measurement method for the eye fatigue caused by HMDs has been widely accepted, we detected parameters related to optometry test. We proposed a novel computational approach for estimation of eye fatigue by providing various verifiable models. RESULTS: We implemented three classifications and two regressions to investigate different feature sets, which led to present two valid assessment models for eye fatigue by employing blinking features and eye movement features with the ground truth of indicators for optometry test. Three graded results and one continuous result were provided by each model, respectively, which caused the whole result to be repeatable and comparable. CONCLUSION: We showed differences between VIMS and eye fatigue, and we also presented a new scheme to assess eye fatigue of HMDs users by analysis of parameters of the eye tracker.

Effect of Heat-Killed Lactobacillus paracasei KW3110 Ingestion on Ocular Disorders Caused by Visual Display Terminal (VDT) Loads: A Randomized, Double-Blind, Placebo-Controlled Parallel-Group Study.

BACKGROUND: Visual display terminals (VDTs) emitting blue light can cause ocular disorders including eye fatigue. Some dietary constituents have been reported to be effective in improving ocular disorders while few clinical studies have been performed. We evaluated the effects of heat-killed Lactobacillus paracasei KW 3110 on improving ocular disorders and symptoms of eye fatigue among healthy human subjects with VDT loads. METHODS: In vitro, the effect of L. paracasei KW3110 on blue light-induced human retinal pigment epithelial (ARPE-19) cell damage. For clinical studies, 62 healthy Japanese volunteers of 35 to 45 years of age who had experienced eye fatigue were randomized into two groups and given a placebo or L. paracasei KW3110-containing supplements for eight weeks. The primary endpoint was changes in VDT load-induced eye fatigue as determined by critical flicker frequency four and eight weeks after the start of supplementation. RESULTS: In vitro, blue light-induced human retinal cell death was suppressed with the culture supernatants of cells treated with L. paracasei KW3110. In clinical study, the VDT load-induced reduction of critical flicker frequency tended to be milder in the L. paracasei KW3110 group when compared with the placebo group during the fourth week. Subgroup analysis classified by the degree of eye fatigue showed that the VDT load-induced reduction of critical flicker frequency was significantly better in the high-level eye fatigue subjects from the L. paracasei KW3110 group when compared with the placebo group during the fourth week (p = 0.020). CONCLUSIONS: L. paracasei KW3110 suppressed blue light-induced retinal pigment epithelial cell death. In the clinical study, ingestion of L. paracasei KW3110 had a potential to improve eye fatigue induced by VDT loads especially high levels of eye fatigue. However, further studies should be required to show more dependable clinical efficacy of L. paracasei KW3110.

Aqueous Extract of Perilla frutescens var. acuta Relaxes the Ciliary Smooth Muscle by Increasing NO/cGMP Content In Vitro and In Vivo.

The leaves of Perilla frutescens var. acuta (PFA) are commonly used as a traditional medicine in Korea, Japan, and China. We previously showed that PFA attenuates eye fatigue by improving visual accommodation through a clinical study. However, detailed mechanisms and chemical compounds have not been studied. In this study, we analyzed the active compounds in an aqueous extract of PFA involved in ciliary muscle relaxation in vitro and in vivo. NMR and MS analyses showed that the PFA extract contained mainly luteolin-7-O-diglucuronide and apigenin-7-O-diglucuronide. The composition after freeze-drying and spray-drying was similar. Freeze-dried PFA (50 µg/mL, 100 µg/mL, and 200 µg/mL) increased nitric oxide and cGMP levels in ciliary muscle cells isolated from the eyes of rats. [Ca2+]i decreased in a dose-dependent manner. Furthermore, Sprague-Dawley rats treated with freeze-dried PFA (200 mg/kg, orally) showed significantly increased cGMP levels compared with the control group and irradiated with white light. Our results suggest that PFA extract has the potential to reduce eye fatigue by relaxing ciliary muscles.

Occupational exposure to fluorescent light in a pathologist with myopic complications and asthenopia onset. / Esposizione professionale alla luce fluorescente in una patologa con complicanze miopiche ed insorgenza di sintomi astenopici.

BACKGROUND: Pathologic myopia is often associated with many complications, e.g. retinopathy, vitreous detachment and glaucoma. To date, occupational exposure of workers suffering from myopic co-morbidities to fluorescence light is not clearly linked to a worsening of retinal damage and eye symptoms. CASE REPORT: A 56-year-old pathologist, suffering from myopic retinopathy and other ocular comorbidities, asked for medical examination due to worsening vision and burning eyes, after occupational exposure to fluorescence microscope. Eye examination performed by an ophthalmologist detected a severe chorio-retinal atrophy in peri-papillar region and scotopic-photopic reduced voltages at electroretinogram. Moreover, a workplace inspection noted high light intensity from power source (9600 lux). Considering severity of the retinopathy, frequency of the ocular symptoms and steady occupational exposure both to low-intensity fluorescent light and high intensity light, we decided to declare the worker only fit for specific tasks which do not include the use of a fluorescence microscope. Almost six months later, the worker was recalled for a new examination and she reported the absence of the ocular discomfort that had led her to request the previous examination. CONCLUSION: In this unconventional case, we considered appropriated to use great caution, to avoid ocular fatigue and prevent possible retinal damage in the worker.