https://www.selleckchem.com/products/mmri62.html Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) signal the environmental light to mediate circadian photoentrainment and sleep-wake cycles. There is high prevalence of circadian and sleep disruption in people with Parkinson's disease, however the underlying mechanisms of these symptoms are not clear. Based on recent evidence of anatomical and functional loss of melanopsin ganglion cells in Parkinson's disease, we evaluate the link between melanopsin function, circadian, and sleep behavior. The pupil light reflex and melanopsin-mediated post-illumination pupil response were measured using chromatic pupillometry in 30 optimally medicated people with Parkinson's disease and 29 age-matched healthy controls. Circadian health was determined using dim light melatonin onset, sleep questionnaires, and actigraphy. Ophthalmic examination quantified eye health and optical coherence tomography measured retinal thickness. The melanopsin-mediated post-illumination pupil response amuption in Parkinson's disease in the presence of normal outer retinal (rod-cone photoreceptor) function. Our findings provide a rationale for designing new treatment approaches in Parkinson's disease through melanopsin photoreceptor-targeted light therapies for improving sleep-wake cycles. Photovoice is a qualitative research tool increasingly utilized in the healthcare field to understand the illness experience from the patient and caregiver perspective. This is the first study to evaluate photovoice in the context of amyotrophic lateral sclerosis (ALS). A patient and caregiver centered research tool was utilized to gain a greater understanding of challenges faced when living with ALS. Eight patients and three corresponding caregivers participating by taking photographs, writing descriptive text, and participating in individual and group interviews. Inductive thematic analysis was employed to uncover recurring themes. Fi