## 6 Discussion  
We undertook a comprehensive review of 21 peer-reviewed publications spanning from 2002 to July 2023, exploring lighting designs that facilitate proper circadian alignment in healthcare environments and their associated health outcomes. The synthesis of these studies suggests that although natural light is integral for establishing a healthy indoor environment, practical limitations related to architectural factors like building forms, orientations, and regional climate hinder the provision of sufficient natural light. Consequently, artificial lighting approaches emerge as a complementary strategy to ensure adequate indoor lighting that meets well-being thresholds for health care facilities. Indeed, evidence-based indoor lighting recommendations for healthy individuals have been recently proposed [77]. Rigorous modeling and clinical studies testing these suggested parameters in an institutional environment will be necessary to provide converging evidence on the appropriate lighting approaches for patients and institutional staff to optimize recovery and well-being. As part of ANSI/IES RP-29-20, a new guideline for healthcare design, recommendations are provided for optimal lighting in hospitals and health care facilities. These guidelines emphasize the diverse lighting requirements of patients, medical professionals, and family members, and they need to be embraced and implemented. Taking into account factors such as color tunable lighting systems and lighting systems that promote good circadian health to improve mood, comfort, sleep, and physical recovery, new standards in medical and healthcare lighting focus on human-centered lighting to improve patient, staff, and visitor experiences [78]. Moreover, these guidelines can serve as a basis for a \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Ref.** & **Research Setting** & **Evaluation Metrics** & **Studies Parameters** & **Software** & **Architectural Elements** \\ \hline \(\left[72\right]\) & Virtual patient room & Circadian stimulus & Lighting intensity, timing, spectrum & Statistical analysis, DAYSIM, field measurements & Window orientation, WWR, glazing material, shading device \\ \(\left[73\right]\) & Virtual patient room & Circadian stimulus & Lighting intensity & Statistical analysis, Radiance, field measurements & WWR, glazing materials, latitude \\ \(\left[75\right]\) & Nursing home & Circadian stimulus, Photopic Lux, EML, CS, plane Lux, M/P & Lighting intensity, timing, spectrum & ALFA & Location, timing, sky condition, materials, luminaires, furniture position \\ \(\left[74\right]\) & Patient room & EML, photopic lux & Lighting intensity, timing & Statistical analysis, Honeybee, Rhino, field measurements & Materials, orientation, WWR location, sky conditions, materials conditions, materials \\ \(\left[76\right]\) & Patient room & Melanopic EDI, melanopic DER, climate-based metrics & Lighting intensity, timing & ALFA & WWR, orientation, location, sky conditions, materials \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Thematic analysis of reviewed papers: simulation-based studies. few design recommendations. In a daytime setting, for instance, an EDI of approximately 250 lux is aimed for during the day. In order to do this, we can increase the availability and accessibility of natural daylight, adjust the spectral content of electrical lighting to increase the amount of melanopic daylight efficacy ratio (DER), enhance surface reflectance and furnishings, and minimize glare to increase the amount of vertical illumination. DER, color rendition index, and energy efficiency should all be taken into account when designing healthcare lighting. The goal in evenings and nights is to enhance visual guidance while minimizing disruption to sleep and circadian rhythms. Sleep environments should be kept below 10 lux, with blackout blinds and orientation lighting as necessary. Melanopic EDI targets can be achieved with warm white LEDs with DERs below 0.35.