Iranian Journal of Ergonomics

Introduction: In an educational environment, the quality of vision is integral to educational progress. Creating visual comfort and increasing efficiency and the desire to study are among the benefits of adjusting the lighting in classrooms and preventing visual impairment in the students. The present study was conducted to evaluate the degree of internal lighting in girls' schools across Hamadan in 2006 and 2014 so as to help identify their potential problems.

Materials and Methods: The present study was conducted in girls' schools across Hamadan on two different occasions –in 2006 and 2014. On each occasion, the average general and local lighting on the classroom blackboards were measured by the recommended methods of the Illuminating Engineering Society of North America on non-sunny days using a Lux Meter and were then compared to the standard limits recommended in the Health and Safety Code of schools and by the Illuminating Engineering Society of North America. In addition to the degree of lighting, certain quality assessment criteria were assessed, including the lighting layout, lamp maintenance, contrast, internal surface cleaning, lighting system maintenance, type of lamps and technical suitability of the design.

Results: Taking the criteria for favorable lighting conditions into account, less than 25% of the sites examined had favorable lighting on both occasions in 2006, only 16% of the classes had favorable general lighting and in 2014, the degree of lighting fell to an unacceptable range in all classes and only 6% of the entire classroom were covered by a standard degree of local lighting on the blackboard. The results also show that surface reflection coefficients are within the desirable range.

Conclusion: The lack of favorable general and local lighting on the blackboard at schools in 2014 and its comparison with the results of the 2006 lighting assessment indicate that providing standard lighting is still a problem for schools. Improper lighting layouts and the use of incandescents or inappropriate light bulbs are among the major causes of poor lighting conditions in girls' school across Hamadan. 

Introduction: Unsuitable and nonstandard tools, insufficient lighting and the lack of adequate rest in carpet weavers leads to an increased prevalence of musculoskeletal disorders in this group of workers that needs to be reduced through the better supervision of carpet weaving workshops.

Materials and Methods: The present descriptive cross-sectional analysis was conducted in rural carpet weaving workshops of Takab, Iran. A total of 86 carpet weaving workshops were selected through cluster sampling, which employed 222 carpet weavers overall. The general and local lighting was measured in the workshops by a photometer (LX-13 model) and the workers' musculoskeletal disorders were assessed using the Nordic Musculoskeletal Questionnaire.

Findings: The results of the study reveal back disorders to have been the most (61.3%) and elbow disorder the least (7.2%) frequent among carpet weavers. The majority of the workshops had a general lighting (82.4% of the workshops) and local lighting (91.9% of the workshops) below the recommended limits.

Conclusion: The extended involvement of the upper limbs in carpet-weaving increases the prevalence of disorders in these organs. The results indicate that the majority of carpet weavers worked in workshops with non-standard lighting. The variables that were most effective in the development of neck and back disorders were the workers' years of work experience and the general lighting at their workplace while the variable that was most effective in the development of wrist and shoulder disorders was the workers' years of work experience only.

Introduction: Few studies were conducted to determine the effects of lighting on cognitive performance. However, they could not reach a decisive conclusion. This study investigated cognitive performance of university students exposed to different levels of lighting under laboratory conditions.

Methods: In this experimental study, 33 subjects (age range 19-26 years) performed cognitive tests. Participants were exposed to three levels of lighting (200, 500 and 1500lux) in laboratory conditions while performing CPT tests to investigate percentage of attention and reaction time machine that measures reaction time.

Results: The results of this study showed that the maximum percentage of attention (99.75%) belonged to lighting of 1500 (lux) and the minimum percentage of attention was related to 500(lux) (99.36%). statistical analysis showed significant differences in percentage of attention in different levels of lighting (P=0.004). In addition, results of data analysis showed that increase in intensity of  lighting can make a significant change in the average response time (P˂0.001), correct response (P=0.004), commission error (P=0.001) and omission error (P=0.017). With increasing the lighting intensity, reaction time has decreased. The reaction time showed significant differences  at all levels of lighting (P˂0.001)

Conclusion: According to the findings of this study, lighting causes a decrease in reaction time and increase in attention. Thus, the lighting should be taken into account while designing of job and tasks which need attention or reaction time.

Introduction: Lighting affects many non-visual functions such as Circadian rhythm, alertness, core body temperature, hormone secretion and sleep. The aim of this study was to investigate the effects of lighting on human cognitive and mental performance.
Methods: In this systematic review, databases including ISI Web of Knowledge, Scopus, PubMed and Science Direct were searched to access the relevant studies. The search was performed using the keywords "Lighting" and "Illumination" and "Cognitive Performance", "Mental Performance", "Memory ", "Attention", and "Concentration" by title, keyword and abstracts of articles published in mentioned databases from 2010 to 2016.
Results: Lighting affects human cognitive performance in three areas of psycho-cognitive (visual comfort, visual perception, color recognition, identification of symbols, attention, working memory, learning, reaction time and brain function), biocognitive area (alertness, mood, vitality, subjective feelings, motivation, well-being and quality of sleep) and mental workload (amount of workload, psychological stress, and mental fatigue). The best light to regulate cognitive, biological (circadian rhythm) and mental processes is bright daylight in the morning with a short wavelength (wavelength 420-480 nm) and high intensity (1000lx).
Conclusions: Lighting design in addition to providing comfort and visual needs should provide the non-visual and cognitive needs such as attention, alertness, mood, sleep quality and decrease mental fatigue and eventually well-bing.

Background and Aim: Undesirable lighting at work environment causes visual and non-visual effects on employers. The aim of this study was to compare the quantity and quality of combined and artificial lighting in daytime and its relationship with the indexes of mental performance.
Methods: This study was carried out at 65 rooms and on 81 employees randomly selected from different clusters. Measurement of lighting parameters was done using a spectrometer. To assess the cognitive function, the Pshycomotor Vigiliance Task (PVT) test and for the sake of visual comfort, alertness and sleep quality, the Conlone, KSS (Karolinska Sleepiness Scale) and PSQI (Pittsburgh Sleep Quality Index) questionnaires were used respectively.
Results: Most artificial sources used in the rooms included fluorescent lights in different shapes and colors. The average indexes of combined lighting was more than artificial lightings (P<0.001). Visual comfort was correlated with high color temperature (P=0.006, r = 0.315). The employees with natural lighting had less visually impairment. The sleep quality of the subjects was related to the type of work environment lighting (Chi²=0.59, P=0.44). Alertness of subjects exposed to high color temperature or natural light was better at 8 and 11 hours. The results of cognitive performance test showed no significant difference between different lighting conditions.
Conclusion: Using natural light or artificial lights with adequate illuminance and high correlated color temperature can increase the alertness and visual comfort to some extent and improve the sleep quality of day staff employers.