Blue-light glasses for sleep difficulties

Inclusion criteria: - Male or female subjects diagnosed with idiopathic PD according to UK Parkinson's Disease Society Brain Bank Clinical Diagnostic Criteria with Hoehn & Yahr stage 2-4 - Ability to obtain written inform consent (IC) for participation in the study - Age of > 30 years (inclusively) - Score of 5 or more on the Pittsburgh Sleep Quality Index score (PSQI) or Excessive daytime sleepiness (EDS) defined by an Epworth Sleepiness Scale (ESS) score of 7 or more - Anti-PD treatment (such as levodopa formulations, dopamine agonists, selective MAO-B inhibitors, anticholinergic agents or amantadine) at a stable dose in the last 30 days prior to the initial screening assessment Exclusion criteria: - Atypical Parkinsonism (Subjects with Parkinsonian features caused by disorder such as multiple system atrophy, progressive supranuclear palsy, dementia with Lewy bodies or multiple brain infarcts) - Severity of Parkinson’s disease defined as stage 1 or 5 according to Hoehn & Yahr stages - Significant cognitive impairment as defined by the Mini-Mental State Examination (MMSE) score <24 - Clinically significant psychiatric illness, including psychotic attacks, major depressive disorder (HAM-D = Hamilton Depression Rating Scale ≥14). Subjects with a lifetime history of suicidal attempt (including an active attempt, interrupted attempt or aborted attempt) - Antidepressant treatment for less than 3 months prior to screening - Participation in other, interventional, research studies - Known conditions associated with sleep disorders other than PD or conditions inferring with the delivery of the blue light treatment: Obstructive sleep apnoea syndrome Eye-related diseases (e.g. cataract, glaucoma, blindness) Any other condition that in the opinion of the investigator may interfere with the interpretation of the study results or constitute a health risk for the subject if he/she takes part in the study Current or history of malignancy or migraine within 5 years before screening Current use or use within three months prior the initial screening of hypnosedative or stimulant drugs such as benzodiazepines or melatonin