Light is generally important for human beings. Visible light supports vision and can modify circadian rhythm, and together with invisible light at longer or shorter wavelength can also make either a direct or indirect impact on human biological and mental health. For medical applications, several studies have shown success in using light to fasten the skin regeneration in burns and to cure diseases such as newborn jaundice. In daily life, an appropriate amount and time exposure to certain types of light can result in rising of alertness and mood improvement, which leads to noticeable growth in one’s productivity. Therefore, human centric lighting can modify lighting factors to make the best of the natural characteristics of light. The seek an ideal indoor lighting system is widely carried out not only by scientists but also by architects. A qualified luminaire is considered by many factors, including luminous productivity, visual comfort and expenses; meanwhile, the idealization of illuminance is also constructed in many ways, such as widening the lamp’s surface area, changing of luminaire’s positions and applying different methods to illuminate a surface. Approaching these problems, our idea is to study the uplighting method and freeform optics using low-cost acrylic lenses. By changing lens shape and optimizing the factors which affect the illuminance such as the irradiation angle and the distance between the luminaire and the reflection surfaces, we find the most effective lens and its peaks due to each factors using the ray-tracing simulation to obtain results concerning high uniformity of illumination.

Context: Lighting conditions significantly influence visual acuity (VA), visual function, and quality of life. Previous research highlighted a correlation between luminance and VA but left a gap in understanding the impact of surrounding luminance. This study focused on investigating the effects of both central and peripheral luminance on VA. Purpose: This study aimed to investigate the influence of both central and surrounding luminance on VA through distance VA measurements. Settings and Design: A dual-component lighting system was utilized, comprising a self-illuminated ETDRS chart and a skyLED system for consistent surrounding illumination. Two experimental setups were conducted: the first varied the central luminance (25 ± 2–341 ± 10 cd/m²), while the second maintained a constant central luminance (150 ± 5 cd/m²) and varied the surrounding luminance (4 ± 2 cd/m² OFF–105 ± 10 cd/m² ON). Methods: Sixty-six participants with refractive errors between 0.0 D and −2.75 D were tested under various lighting conditions. Both uncorrected refractive error (URE) and corrected refractive error (CRE) eyes were evaluated. Statistical Analysis Used: Paired t -tests were used to evaluate the statistical significance of differences in VA scores. Results: Experiment 1 demonstrated a significant increase in VA scores, with mean improvements of −0.120 LogMAR for URE eyes and −0.073 LogMAR for CRE eyes as chart luminance increased from 26 cd/m² to 153 cd/m². Experiment 2 further showed a notable improvement in VA scores under varied surrounding luminance conditions, with mean improvements of − 0.118 LogMAR for URE eyes and −0.073 LogMAR for CRE eyes as luminance increased from 4 cd/m² to 102 cd/m². Conclusions: This study emphasizes the significant impact of both central and peripheral luminance on VA. The introduction of the skyLED lighting system underlines the importance of optimal lighting for visual performance.

This study examines the transformative impact of integrating pendant asymmetric lens (PAL) and blackboard asymmetric lens (BAL) LED luminaires to enhance classroom lighting, with the goals of replicating the ambient effects of natural daylight and promoting energy efficiency. This research focuses on improving the quality of learning environments through uniform, soft, and diffused lighting, which mimics sky-like illumination while adhering to sustainable energy practices. Advanced asymmetric lens LED luminaires are employed to achieve optimal lighting distribution, as indicated by luminous intensity distribution curves. Comparative analyses in diverse educational settings reveal significant improvements in ceiling illuminance, ranging from 935 to 1000 lx, and workspace illuminance from 660 to 720 lx, with reduced glare (UGR < 10). This results in bright, visually comfortable spaces conducive to learning. Additionally, the PAL and BAL solutions outperform conventional lighting systems like stretched ceilings and lightboxes by maintaining clear overhead spaces, eliminating shadows, and offering cost-effective solutions. This successful integration demonstrates a notable advancement in the development of energy-efficient, visually comfortable educational environments, contributing to the goals of sustainability and improved well-being for both students and teachers.

This research is dedicated to the exploration of sophisticated methodologies and the creation of a high-precision system for pupil size measurement that is capable of displaying real-time results. The comprehensive system encompasses an infrared camera, an infrared LED light, an LED light box designed for pupil stimulation, and robust control software that enables analysis, measurement, and real-time documentation of results. Our study yielded promising results with a high degree of precision in pupil size measurements, thereby opening new possibilities for intricate vision-related research and applications. With its potential impact, the system can offer profound contributions to areas including eye-health diagnosis, human-computer interaction research, and studies focusing on light-induced pupil response.

Indoor lighting environment significantly impacts students’ concentration and learning performance. Optimal lighting conditions enhance reading speed, accuracy, and comprehension abilities. In contrast, poor lighting conditions may lead to decreased concentration and increased errors in tasks. Therefore, classroom lighting is an important factor to consider in classroom design to optimize cognitive efficiency of students. Current classroom lighting solutions using LED systems have met European Norm (EN) standard in terms of illuminance and energy efficiency. However, although the issue of glare has been addressed, it has not been completely resolved. This study introduces a solution for glare-free classroom lighting that maintains uniformity while adhering to existing standards. This approach aims to create a visually comfortable learning environment, balancing effective lighting with glare reduction.

This study presents a significant advancement in LED interior lighting through the development and application of Asymmetric Lens–Total Internal Reflection (AL–TIR) optics, with a focus on enhancing lighting uniformity and indoor comfort by simulating sky-like lighting distribution. AL–TIR technology employs asymmetric lenses combined with total internal reflection to efficiently redirect and spread light, achieving a controlled and even ceiling illumination suitable for various interior applications. This research explored the establishment of ideal luminous intensity curves, devised practical AL–TIR optical designs through numerical calculations, and conducted extensive simulations to assess performance in typical indoor environments. Our findings demonstrated substantial improvements in lighting uniformity, with the AL and AL–TIR systems achieving direct illuminance uniformities of 0.78 and 0.83, respectively, compared to traditional tube LEDs at 0.25. These results, validated in several office rooms, highlight the efficacy of AL–TIR optics in revolutionizing indoor lighting design by balancing optimal lighting distribution with occupant comfort and well-being.