*4.2. Problems with Poor Lighting in the Classroom*

Winterbottom and Wilkins [81] measured, in 90 secondary school classrooms, with the variable of flicker, the lighting of the desks and the blackboards. The results showed that 80% of the classrooms were illuminated with fluorescents, which can cause headaches and impair visual task performance. While the illuminance (from excessive day and artificial lighting) was in excess of the recommended levels in 88% of the classrooms, in 84% it exceeded the levels to a degree that visual comfort would decrease. The lighting was not always adequately controlled, depending on the class design and infrastructure. The ambient light needed for close work at desks reduced the contrast of images. Venetian blinds in 23% of the classrooms had spatial features suitable for inducing glare. These findings provided information on small-scale reports linking student performance, behavior, and learning to classroom lighting. In rooms where there is no uniform lighting, when the immediate task area is brighter than the surrounding area, the effects of glare can be significant. Compared to the recommendations of the Chartered Institution of Building Services (2004) [82], the lighting varied from inadequate to excessive. It is important to note that the data for this study were collected in the summer months, when daily lighting may have been higher than the average for the year.

Winterbottom and Wilkins [81] stated in their article that there are numerous studies that have also noted changes in behavior under particular forms of lighting. Schreiber (1996) [83] suggested that children are more relaxed and interested in activities when classroom brightness is reduced; while Shapiro, Roth, and Marcus (2001) [84] found that maladaptive behaviors were less frequent under indirect full-spectrum fluorescents. Rittner and Robbin (2002) [85] indicated that daylight helps students retain and learn information. Some authors have emphasized the importance of daylighting, but with the need for integrative systems of natural and artificial light.

CIBSE (2004) [86] provides lighting design recommendations for different types of classrooms, in the range of 300 lx to 500 lx; the adoption of such values helps to restrict glare to reasonable levels (it is worth noting that a new installation with new lamps and clean surfaces can provide 25% more lighting than the designed lighting, and only half as much as the initial lighting is present when the lamps are old and dirt has accumulated).

Ho et al. [87] conducted a study to minimize classroom lighting costs in Taiwan by taking advantage of natural light. In their article, they state that there is ample evidence of the damage caused to children's vision as a result of poor lighting conditions in classrooms. Optimal shading of classroom windows is important to improve daylight illumination in the subtropics.

Guan and Yan (2016) [88] state that daylight varies greatly due to the movement of the sun, changing seasons, and various climatic conditions. Customized static light assessments, known as static daylight assessments, representing simulations of only one time of the year or one time of the day, are inadequate for evaluating the dynamics of daylight variability. Using the graphic tool Temporal Map to display annual daylight data, this study compared different passive architectural design strategies under climatic conditions of five representative cities and selected the most appropriate schematic design for each city, which in turn was integrated with the Chinese academic calendar to obtain an improvement in occupational time. This modified map connected design work with human activity, making the daylight evaluation more accurate and efficient. In addition, the prevalence rate of myopia is extremely high among young Chinese people according to current government statistics [89]: up to 40.89%, 67.33%, and 79.2% in primary, junior, and high school, respectively, and remarkably, 84.72% in university. In fact, the database, derived from the national adolescent health survey conducted every five years, shows that nearsightedness ratios have been steadily rising in recent decades [89–91]. Meanwhile, high levels of light have been shown to have preventive effects for myopia [92,93]. Given the potential energy savings and health benefits for students, improving the quality of light in such environments must be a priority.
