Adequate illumination plays an important part in providing a healthy environment for nursing home patients with dementia. With increasing awareness of non-visual responses to light, new approaches to quantifying illuminance have emerged. In the present study, we assessed the illuminance in nursing home dementia units in terms of melanopic equivalent daylight illuminance, a metric which aims to quantify the non-visual physiological effects of light by weighing irradiance according to non-visual photoreception. It is among the most comprehensive studies of light conditions conducted in dementia units in terms of melanopic equivalent daylight illuminance to date, and the first to elucidate seasonal differences in melanopic illumination. Light conditions were assessed in all 15 nursing homes with dedicated long-term dementia units in Bergen municipality (60.39°N), Norway, during summer and winter. Results indicated that seasonal differences and gaze direction had some impact on melanopic equivalent daylight illuminance, but most measurements still fell below even conservative recommendations across seasons. The findings indicate a need for additional light sources that can compensate for limited natural daylight in dementia units. The ubiquity of insufficient melanopic equivalent daylight illuminance in dementia units suggests a role for lighting interventions in future research seeking to improve entrainment, sleep and mental health of dementia unit residents.

充足的照明在为老年痴呆症患者提供健康的环境中起着重要的作用。随着人们对光的非视觉反应的认识不断提高，出现了量化照度的新方法。在本研究中，我们根据黑素等效日光照度评估了疗养院痴呆症单位的照度，该指标旨在通过根据非视觉光接收权衡辐照度来量化光的非视觉生理效应。迄今为止，它是对痴呆症患者进行的有关黑素体等效日照度的最全面的光条件研究之一，也是第一个阐明黑素体照度的季节性差异的研究。在夏季和冬季，对挪威卑尔根市（60.39°N）的所有设有长期痴呆症长期护理单位的15家疗养院进行了光照条件评估。结果表明，季节差异和凝视方向对黑素等效日光照度有一定影响，但大多数测量值仍低于整个季节的保守建议。研究结果表明需要额外的光源，以补偿痴呆症单位中有限的自然日光。痴呆症患者黑素等效当量照度普遍存在，这表明照明干预在未来研究中的作用是寻求改善痴呆症患者的病情，睡眠和精神健康。结果表明，季节差异和凝视方向对黑素等效日光照度有一定影响，但大多数测量值仍低于整个季节的保守建议。研究结果表明需要额外的光源，以补偿痴呆症单位中有限的自然日光。痴呆症患者黑素等效当量照度普遍存在，这表明照明干预在未来研究中的作用是寻求改善痴呆症患者的病情，睡眠和精神健康。结果表明，季节差异和凝视方向对黑素等效日光照度有一定影响，但大多数测量值仍低于整个季节的保守建议。研究结果表明需要额外的光源，以补偿痴呆症单位中有限的自然日光。痴呆症患者黑素等效当量照度普遍存在，这表明照明干预在未来研究中的作用是寻求改善痴呆症患者的病情，睡眠和精神健康。