Integration Gaps in Smart Indoor Lighting: A Systematic Bibliometric Review of Human-Centric Control, IoT, and Event-Driven Automation

Abstract

Lighting systems constitute a significant share of building energy demand while simultaneously affecting visual comfort, circadian regulation, cognitive performance, and occupant well-being. Despite rapid advances in smart building technologies and adaptive illumination systems, the literature remains fragmented regarding the integration of optimization intelligence, interoperable Internet of Things (IoT) infrastructures, and event-driven automation frameworks within unified human-centric lighting environments. This study presents a systematic bibliometric and thematic review of smart indoor lighting research published between 2015 and 2024, following the PRISMA 2020 framework across Scopus, Web of Science, and IEEE Xplore. From an initial corpus of 5,529 records, 30 studies satisfied the final inclusion criteria requiring simultaneous reporting of quantitative performance outcomes alongside explicitly defined control or automation mechanisms. Bibliometric analyses using MATLAB and VOSviewer revealed strong growth in adaptive lighting and IoT-enabled infrastructures, with Annual Average Growth Rates reaching 9.2% for occupant-centred lighting, 7.3% for energy-oriented lighting, and 13.9% for sensing and communication infrastructures. However, metadata-level integration between hyper-heuristics, interoperable IoT middleware, and Event–Condition–Action (ECA) and IFTTT automation remained extremely limited, with a mean Jaccard co-occurrence coefficient of only 0.018, indicating weak cross-domain coupling. Thematic metrics show uneven adoption: Equivalent Melanopic Lux (EML) is reported in 20% of core studies, Circadian Stimulus (CS) in 27%, while Unified Glare Rating (UGR) remains under-reported at 13.3%, highlighting a methodological gap in visual comfort assessment. The findings demonstrate that smart indoor lighting research continues to evolve through disconnected disciplinary trajectories rather than cohesive intelligent control ecosystems. This review proposes a conceptual integration framework and future research roadmap aimed at supporting interoperable, energy-efficient, and human-centric lighting systems capable of simultaneously optimizing automation performance, occupant comfort, and non-visual health outcomes within intelligent indoor environments.