Visual Discomfort Research Articles

Effects of anti-fatigue lenses on performance, muscle activity and subjective discomfort responses during a seated computer task

Anti-fatigue lenses (AFL) intend to provide health benefits in association with computer work. Their effects on visual and muscle discomfort mechanisms and task performance remain unclear. Twenty-three computer users (n = 12 males) underwent two 90-min computer sessions with AFL or placebo lenses. Eye strain, body discomfort, typing performance, upper trapezius (UT) activation amplitude and variability, and neck posture were analyzed for time, condition, and sex effects. No significant effects of condition were observed on the dependent measures evaluated. Discomfort increased over time (neck/shoulder: p < .001), more so in females (eye strain: p < .001). Females’ UT activation amplitude was negatively correlated to eye strain in the placebo condition (p = .05).

Potential of Photonic Effects of Ion-Spec Medical Design in Controlling symptomatic characteristics in people with headache, high blood pressure and intraocular pressure

IONSPEC –A nanobiophotonic medical design incorporated negative ions and far infrared rays (FIR) wasdeveloped in helping patients in reducing their bifrontal discomforts, visual discomforts, and headaches.Both aerobic and not aerobic conditions help eye pressure at a healthier level, and their vision discomfortsrelief after wearing IONSPEC correction. The results suggest that materials emitting FIR, which are widelyused in Asia for therapeutic and preventative purposes, appear capable of reducing bifrontal pains due tovisual discomfort, and a headache without side effects. This study will hopefully enlighten professionals onspreading awareness regarding health hazards of computers and IONSPEC nanobiophotonic medicaldesign has a potential to reduce eye pains, headaches, and othe visual symptomatic in many eye conditions

Exploitation of indoor illumination for typical flat dwellings in the Mediterranean area

The 2018/844 Energy Performance of Buildings Directive (EU) has widened the scope of appropriate design of buildings from a pure energy performance and carbon emissions perspective to a wider scope that includes indoor comfort, and indoor air quality among others. To this effect, external parameters, especially solar energy, have a strong impact on the energy performance of buildings in Mediterranean regions, which requires careful consideration when it comes to benefiting from natural lighting while avoiding solar overheating. This paper addresses the considerations of natural lighting in the deep renovation of a housing block in the Mediterranean climate of the Republic of Malta, comparing some of the usual illuminance ranges to achieve optimal conditions based on international recommendations. DesignBuilder v7.0.0.102 has been the selected software to model the building that has been calibrated through experimental measurements. The model enabled the natural lighting conditions in the building evaluated and the effectiveness of suggested improvements to be determined. Results pointed out that the building under study satisfies the international standards about the prevention of visual discomfort only. Increasing the size of windows in identified zones, especially the first floor, was found to help improve other natural lighting characteristics. One of the proposed designs (Model 6) that replaces single-glazed with double-glazed windows that include an external spectrally-selective coating would significantly improve access to natural light bringing the building closer to the recommended levels of Annual Sunlight Exposure and reducing artificial lighting usage by up to five times. The relocation of room spaces could also reduce the use of artificial lighting.

COMPUTER VISION SYNDROME: EPIDEMIC AMONG MEDICAL STUDENTS IN BULGARIA

PURPOSE: The aim of оur research is to assess the impact of monitor use and computer learning process on the visual comfort and ocular health of students from Medical Universities in Bulgaria. METHODS: 219 students participated in the study. They were interviewed anonymously in January 2023, through an online survey. Questions concern students’ ocular and visual comfort during the proсess of self-preparation for exams during session. RESULTS: Тhe survey results indicate that digital learning increases screen time at potentially dangerous for eye health levels. The most common complaints among students are eye fatigue (83.1%), tearing (58.9%), dry eyes (58.4%), blurred vision (40.2%), photophobia (37.4%), and itchiness (34.7%). Results show that 32% of respondents spent 1-2 hours working on a computer without a break; 57.1% reported that they work for more than 2 hours, and only 3.7% spent less than 20 min before taking a break. CONCLUSIONS: It was noted that eye fatigue and visual discomfort among medical students were negatively affected by the monitor learning during the session. Increased screen time causes digital eye strain, which impairs life quality and is a socially significant phenomenon.

Persistent Xerophthalmia in a Patient with Rheumatological Disease and Priiviary Sjogren’s Syndrome: Case Report from Northern Brazil

This case study aims to contribute to the literature in order to highlight the importance of this collaboration between medical specialties. A female patient R.N.N. F, age 66, from the city of Manaus, with a previous diagnosis of Sjogren’s syndrome in regular follow-up by the Rheumatology team at the Araujo Lima outpatient clinic and referred to the Ophthalmology sector for complementary evaluation related to visual discomfort. The fundoscopy performed in the patient was within normal limits, but the symptoms experienced by her proved to be an important clinical finding, which has ratified the need for regular and multidisciplinary follow-up. This report unequivocally demonstrates that even in the face of tests considered within the expected limits for a given population, the clinical presentation can be specific and particular for each analyzed individual. Early screening exams should contemplate the patient in a holistic and individualized way whenever possible.

A Pilot Study on the Effect of Daylighting and Orientation in the Office Building: A Case of Kathmandu

Illuminance results in visibility of objects and daylighting is the major source of light for perceiving and carrying out certain function. Office blocks hold the space for people to perform economic task for 7-8 hours daily and humans seek comfort. Lighting the interior is a mindful job, as the space can be over lit or under lit resulting in visual discomfort and high use of energy to maintain human comfort. Quality and quantity of natural light in the indoor is guided by several factors such as climate, latitude, sky condition, site obstructions, orientation, opening design, surface reflectivity, space function etc. The study shows that the best orientation for Kathmandu is 175°N and for the building with window wall ratio greater than 60%, orientation does not play a vital role. Autodesk Ecotect 2011, has been used to simulate the building with the real case scenario in the urban context for the outmost result. The finding adds value during the early design phase and also to prepare guidelines, policies and bylaws relating to wellbeing of occupant for visually and functionally friendly interior.

Reasonable use of Indoor Lighting in Human Living Environment

In today's life, lighting design has become a very important part of the indoor environment, affecting not only the presentation of the design, but also human health. In current lighting designs, there is still a lack of attention to the use of lighting, resulting in visual and health discomfort for occupants. Based on the original light research, this paper analyzes and applies the light to explore the most scientific direction of light use. Analysis of color temperature, light flux, illumination, and other data of lighting types on the market, and investigation of the effect on human perception. The types of lighting should also not be harmful to the eye and safe to use for long periods of time. Reflective materials are another alternative method to reflect natural lighting to the room to bring spaciousness when there is no available natural lighting directly. In the future, there should be experimental lighting that may mimic or replace lighting in nature, or lighting that is fully adapted to the user's senses, emotions, and fatigue. This paper looks forward to finding more appropriate ways to use interior lighting and is dedicated to addressing unreasonable lighting designs in interior design.

Difficulties in Performing Daily Activities in Patients with Dry Eye before and after Treatment.

This research consists of a cross-sectional study of 121 patients, with a mean age of 70 ± 9 years, diagnosed with DED. All patients were treated in the University Clinic for Ophthalmology in "St. Spiridon" Emergency Hospital, Iasi. For all patients, we evaluated visual acuity on the Snellen chart, tear breakup time (TBUT), Schirmer I test scores, and contrast sensitivity. For this study, we used the Visual Functioning Questionnaire-25 (VFQ-25) version 2000, modified and adapted for this research (19 items). Prior to treatment, patients had very high difficulty reading a text in a newspaper or on TV, reading prices on products in shops, or recognizing people they already met. Performing manual work or favorite activities was also very difficult. Post-treatment visual challenges improved in the majority of cases, regardless of the treatment method used. We found that symptomatic dry eye disease was associated with reduced ability in performing several important vision-related daily tasks and has a significant impact on life quality and visual performance.

Reliability Enhancement Driven by ANN for Lighting Control System in Highway Tunnels

Compared with open roadways, traffic safety in highway tunnels requires more attention to build smoothly transitioned and well-coupled light environments for drivers to alleviate visual discomfort so as to achieve a balanced sense of driving safety and comfort. In this study, in order to overcome the drawbacks of existing tunnel lighting control modes that disregard the color temperature of natural light characteristics and collaborative influence of color temperature and luminance of natural light on tunnel lighting quality, one artificial neural network (ANN) model is designed and trained to simulate one physical lighting control system that takes into consideration color temperature and luminance simultaneously. In this model, multiple parameters of discrete and continuous types of input layer and output layer are synergistically analyzed. The model was also trained with quantities of field data from one tunnel in service and includes one hidden layer with 10 neurons. The simulation results showed that this model obtains a high degree of fitness with inside luminance and 100% recognition rate with inside color temperature in the threshold zone, which conforms to the regulation strategy of actual lighting control systems with high confidence. The proposed model will greatly enhance the reliability and sustainability of the lighting system during its normal operation, which can also support other lighting scenarios due to its flexibility and scalability with multiple-input and multiple-output (MIMO) capabilities.

Temperament as a risk factor for drug addiction in young adults

Aim of the studyAim: The aim of this study was to assess the relationship between temperament and addiction to psychoactive substances in young adults.Subject or material and methodsMethods: 74 young adults participated in the study: 37 with substance use disorder and 37 controls, aged 18-28 years. They completed Rothbart’s Adult Temperament Questionnaire (ATQ) and a socio-demographic survey. The study was conducted in the Center for Treatment, Therapy and Rehabilitation, run by the MONAR Association.ResultsResults: Our results indicate significant differences between the test group and the control group in the following temperamental traits (p &lt;0.05): Endogenous Sadness, Visual Discomfort, Inhibitory Control, Attentional Shifting, Sociability and Intense Environmental Pleasure. Compared to controls, persons with substance use disorder scored higher on endogenous sadness and intense environmental pleasure. Greater endogenous sadness suggests they experience more negative emotions and lower mood as a result of disappointment or loss, which promotes development of addiction.DiscussionDiscussion: This study demonstrates differences in the severity of some temperamental traits between persons with substance use disorder and control group.ConclusionsIt is suggesting that temperament can be a risk factor for addiction to psychoactive substances.

Real-Time Investigations and Simulation on the Impact of Lighting Ambience on Circadian Stimulus

Indoor lighting, incorporated with visual and circadian needs, is the upcoming goal of lighting designers. In tropical and subtropical regions, where more daylight is available, daylight harvesting is a prime source of ambient lighting indoors. This paper aims to study various cases of lighting ambience to investigate the circadian lighting capability in terms of the circadian stimulus (CS) of the system under consideration. The instances considered are simulation studies in an open office plan and real-time experimentations in a test workbench and a faculty cabin. Daylight integration was undertaken through controlled venetian blinds, tunable sources and a commercially available human-centric lighting system. The result and analysis show the influence of spectrally tunable light sources on CS rather than fixed light sources. Due to the varying CCT of tunable LED luminaire, circadian stimulation for an occupant can be easily incorporated without crossing the limits of vertical and horizontal illuminance, which may lead to visual discomfort. The findings from this study reveal that daylight–artificial light integration scheme with controlled shading and spectrally tunable source provides the optimal solution for glare-free, energy-effective and circadian entrainment, i.e. human-centric lighting (HCL). With the help of simulations, pre-evaluation will aid the lighting engineers in making a better choice among the various lighting-controlled schemes to implement HCL in indoor office spaces.

Thermo-responsive and mucoadhesive gels for the treatment of cystinosis

Mucoadhesive thermogels were developed by crosslinking poly(n-isopropylacrylamide) based polymers with chitosan and incorporating disulfide bridges, capable of releasing cysteamine upon interaction with mucin, for the treatment of cystinosis. Through crosslinking with chitosan and incorporating varying concentrations of the disulfide monomer into the polymer backbone, the extent of how mucoadhesive the developed thermogels were could be controlled. Through disulfide bridging with mucin, the thermogels released 6 to 10 μg of the conjugate model 2-mercaptopyridine over five days. Utilizing chitosan as the crosslinker, the developed thermogels were shown to degrade to a statistically higher extent following incubation with lysozyme, the highest concentration tear enzyme, by gravimetric and rheologic analysis. The developed thermogels were extensively tested in vivo utilizing a rat model in which materials were applied directly to the corneal surface and a rabbit model in which thermogels were applied to the inferior fornix. With the developed models, there was no adverse reactions or visual discomfort incurred following application of the thermogels. It has been demonstrated that the thermogels produced can be applied to the inferior fornix and release the stable conjugated payload over several days. The developed thermogel was designed to improve upon the current clinical treatment options for ocular cystinosis which are acidic topical formulations that require reapplication multiple times a day.

How Visual Discomfort Is Affected by Colour Saturation: A fNIRS Study

The wide colour gamut displays have improved the viewing experience greatly. However, highly saturated colours may also bring problems such as visual discomfort. In this study, the influence of colour saturation on visual discomfort is investigated. Visual stimuli sequences with different images and saturation levels were presented in subjective and objective experiments. The scores of image quality, visual comfort, and preference were collected in questionnaires. The peak amplitude of heamodynamic response was extracted from fNIRS. The results show that, in the mid saturation level, subjective evaluation on visual discomfort was the lowest and the smallest peak amplitude of heamodynamic response was observed. While the image quality and preference increased as the saturation increased. For wide colour gamut displays, the visual discomfort induced by highly saturated colours should be taken into consideration.

Colour‐related, binocular interactions in patients with dyschromatopsia

AbstractWe report findings of monocular and binocular assessments of colour vision and thresholds for rod‐ and cone‐mediated sensitivity in two young patients (P1 and P2) diagnosed with monocular dyschromatopsia. Altered, monocular, colour perception with no clear diagnosis was reported in each patient based on results from a number of clinical visual assessment tests carried out over several years. Electrodiagnostic tests also revealed reduced Yellow / Blue (YB) chromatic sensitivity in P1. Both patients exhibited unexpected binocular interactions of colour signals. This abstract focuses mostly on the results obtained in P1, but similar results using the same visual assessment tests will also be presented for P2.P1 experienced visual discomfort, often manifested as differences between monocular and binocular viewing, noise‐like appearance of uniform fields and colours over the field, when viewed monocularly with either eye. As a result of these reports, we re‐examined P1's visual deficits using the Colour Assessment and Diagnosis (CAD) and the Flicker‐Plus (FP) tests (http://www.city-occupational.co.uk/). The FP test measures rod‐ and cone‐mediated rapid flicker sensitivity centrally (along the direction of gaze) and at 6 deg eccentricity in each of the four quadrants.Colour Vision. P1 shows significant loss of YB colour vision when tested monocularly in the right eye, but normal red‐green (RG) and YB colour vision in the left eye. When tested binocularly, P1 continues to show the same loss of YB colour vision observed when using only the right eye. These results were unexpected since P1 shows ‘normal’ binocular summation for both colour and flicker sensitivity, even when the thresholds are above the normal range.Rod‐ / Cone‐sensitivity. The patient's cone‐mediated, flicker sensitivity at all five locations investigated (under binocular viewing) was normal (with flicker detection thresholds, often under 2%), but only for the cone‐enhanced condition. When tested with rod‐enhanced stimuli, P1 shows much reduced sensitivity with larger thresholds in the periphery, but only in binocular viewing. Such responses have not been observed previously.In conclusion, P1 shows loss of YB colour vision in the right eye and also significant loss of rod‐mediated sensitivity at each of the five locations investigated. The patient's cone mediated thresholds, at every location tested, were consistently below the mean expected for normal trichromats, both binocularly and with each eye. The YB colour vision measured binocularly remained severely abnormal with thresholds similar to the right eye, in spite of normal colour vision in the left eye. Preliminary observations also suggest that the patient's colour and rapid flicker sensitivity can be affected by fatigue and other factors.Although patient, P2, varied significantly to P1 in monocular thresholds, a similar binocular, inhibitory interaction between the two eyes was observed when processing colour signals. These observations and the unusual interactions between signals derived from the two eyes point towards abnormal central processing of colour signals.

Accommodation Response Variations in University Students under High Demand for Near-Vision Activity.

The objective of this study was to investigate accommodation changes and visual discomfort in a university student population after a period of high demand for near-vision activity. A total of 50 university students aged between 20 and 22 years were recruited. The tests performed involved positive relative accommodation (PRA), negative relative accommodation (NRA), accommodation amplitude (AA), and monocular and binocular accommodative facility (MAF and BAF). Visual discomfort was measured on a scale involving a visual discomfort questionnaire (VDQ). All accommodative variables underwent changes during the exam period; specifically, regarding NRA and PRA, 30.4% and 15.1% of the studied population, respectively, appeared to be below average. Moreover, 42.3% of the population exhibited values below average in the second measure of AA. On the other hand, a small percentage of the population was below average in MAF and BAF measurements: 3% in the monocular right eye test, 6% in the left eye test, and 9.1% in the binocular facility test. Finally, the VDQ score did not reveal a statistically significant difference between the two measurements. Prolonged near-distance work, such as a university exams period, changed all accommodation systems (amplitude of accommodation, relative accommodation, and accommodation facility). These changes influence an accommodation excess that results in blurred vision, headache, and problems with focusing.

The relationship between visual discomfort and cortical excitability in cone-opponent stimuli

Increased colour contrast can induce visual discomfort, but there is little research on the effect of hue. Colour is processed via one or more information streams or channels. We hypothesized that hues which activate more than one channel would induce greater visual discomfort, as they will demand greater neural resources. Normally-sighted young observers made discomfort judgments of isoluminant stimuli of varying hue and contrast whilst EEG was recorded. As predicted, stimuli recruiting more than one channel were more uncomfortable, and this increased with contrast. Uncomfortable stimuli showed increased N2 event-related potentials and decreased alpha-band oscillations, potentially indicating increased neural excitability. This is evidence that increased neural responses are related to visual discomfort for chromatic stimuli. Furthermore, it suggests that the origins of visual discomfort are in early visual areas, when colour is represented in a cone-opponent space, rather than later areas where colour representation is determined by perceptual similarity.

Accommodation and Vergence Responses to Electronic Holographic Displays and Super Multiview Holographic Stereograms

Electronic holography is an ideal 3-D display technique to ameliorate the vergence-accommodation conflict, which is a possible cause of visual fatigue and discomfort from viewing conventional stereoscopic 3-D displays. Previous studies have measured accommodative and vergence responses to holographic images and to real objects, and the results showed that these responses are in good agreement. To demonstrate the effectiveness of electronic holography as a possible solution to the vergence-accommodation conflict caused by viewing conventional stereoscopic 3-D displays, we measured both accommodative and vergence responses to reconstructed images of holograms and super multiview holographic stereograms. We also measured responses to real objects located at various distances and conventional two-view stereo images for comparison. The results indicate that the accommodative responses to the electro-holographic display and super multiview holographic stereogram change with the vergence response in a similar manner, as is the case with real objects as compared to conventional two-view stereo display. This suggests that the electronic holographic display and super multiview holographic stereograms are promising candidates for resolving the vergence-accommodation conflict.

Effects of a Traction Device for Head Weight Reduction and Neutral Alignment during Sedentary Visual Display Terminal (VDT) Work on Postural Alignment, Muscle Properties, Hemodynamics, Preference, and Working Memory Performance.

The forward head posture of visual display terminal (VDT) users induces various physical and cognitive clinical symptoms. However, few studies have been conducted to identify and solve problems associated with VDT posture. This study aimed to examine the adverse effects of VDT posture and the positive effects of traction-combined workstations by measuring postural alignment, muscle properties, blood velocity, preference, and working memory. Thirty-four healthy VDT users (18 males and 16 females aged 20-30 years) participated in the experiment at three workstations, including conventional (VDT_C), head support (VDT_S), and upright (VDT_U) workstations. They conducted 2-back working memory task. The craniovertebral angle (CVA), muscle tone and stiffness, blood velocity and visual analogue discomfort scale (VADS) were measured to examine the influence of workstations. VDT_C showed increased muscle tone or stiffness in the levator scapulae (LS), suboccipital muscle (SM), and sternocleidomastoid muscle (SCM) and an increased reaction time (RT) in working memory. However, VDT_S showed decreased stiffness and tone of SM and improved comfort. In addition, VDT_U showed decreased stiffness or tone of the LS and SCM and improved blood velocity and RT. In conclusion, maintaining neutral alignment significantly improved working memory performance, muscle properties, and blood velocity.

Keep It Brief: Videoconferencing Frequency and Duration as Predictors of Visual and Body Discomfort

The recent COVID-19 pandemic has led to a drastic increase in the frequency of videoconferencing used for work, school, and socialization. To date, the user experience impact of this increased screen time is unknown. We surveyed 489 participants (M age = 24.19, Range = 18–72) to determine which factors best predict visual and body discomfort. Along with gender, screen time, and level of subjective meeting fatigue, meeting duration significantly predicted visual discomfort. In contrast, meeting frequency (along with the level of meeting engagement, subjective meeting fatigue, and other covariates) significantly predicted bodily discomfort. These results highlight the need for greater ergonomic evaluation of work-from-home setups, as well as point to a need for shorter, fewer, and more engaging video meetings for the average worker from home.

Experimental study on the impact of double tilted Venetian blinds on indoor daylight conditions

One of the most important concerns when designing buildings as liveable spaces is the indoor comfort. This depends on different factors, including daylight availability and discomfort glare conditions.The increasing use of glazing areas in the building's envelopes can lead to high energy consumption and problems such as visual discomfort. The use of shading devices stands out as a sustainable design strategy to reduce energy consumption in the buildings. This work presents an experimental analysis of the impact of an innovative shading device, a double-tilted venetian blind (DTVB) with different positions of upper and lower slats, on the indoor daylight conditions. Moreover, discomfort glare evaluation, through DGPs metric, is performed.The experimental campaign was conducted in an outdoor test cell during three periods of the year: summer solstice, winter solstice and autumn equinox. Experiments were carried out with both white and grey DTVBs, for several positions of upper and lower slats, under clear and overcast sky conditions. This comprises the measurement of indoor and outdoor horizontal and vertical illuminances and irradiances and solar and visible transmittance of the fenestration. It was concluded that DTVBs can achieve a higher performance, regarding solar protection, daylighting and glare control, when compared with more traditional venetian blinds systems.