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The Radboud University Medical Center in Nijmegen carries out a lot of research into Parkinson’s disease. A phased investigation is currently being conducted into the possibilities of using blue light in Parkinson’s patients. Propeaq glasses with blue light have been introduced as a possible new method to treat sleep and mood disorders in patients with Parkinson’s disease (PD). Assessing patient acceptance is an important first step towards formal testing and introduction to clinical practice. The results of the first phase were published in Parkinson’s Disease (Hindawi) Volume 2019 in June. Below is a summary and a link to the publication.


Blue light glasses have been introduced as a possible new method to treat sleep disturbances in patients with Parkinson disease (PD). Assessing patient experiences represents a key step in the road towards formal testing and introduction into clinical practice. Fifty-eight PD patients have used the blue light glasses for at least one week. 74% of respondents reported subjective improvements in night-time sleep, daytime sleepiness, depressive symptoms, motor functioning, or a combination thereof. Except for one patient, all responders would like to continue using the glasses, mostly because they considered it a useful aid. Conclusion. Blue light therapy appears to have a positive effect on sleep, mood, and motor symptoms in PD. PD patients had an overall positive attitude towards blue light glasses as treatment for sleep disorders.

Circadian system

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the coexistence of motor and nonmotor symptoms. Sleep disturbances are among the most common nonmotor symptoms, occurring in up to 90% of PD patients; these sleep disorders reduce quality of life and hamper daytime functioning. In PD, the circadian system appears to have an impact on motor and nonmotor symptoms. For example, deterioration of motor symptoms (rigidity, tremor, and bradykinesia) reveals abnormal circadian patterns with PD symptoms worsening throughout the day.


Although many different pharmacological and non-pharmacological strategies have been introduced to manage sleep problems in PD, their efficiency remains limited. Sleep medications often result in side effects and sometimes even in worsening of PD symptoms.

Blue light

Blue light is more effective in entraining the biological clock compared to traditional lightboxes with white light. These glasses emit blue light through integrated LED light sources with a wavelength of approximately 468nm at a light intensity of 40 Lux at 1.5 cm (0,9 µW/cm2) from the eyes.


An online survey was conducted on February and March 2018 amongst patients who had purchased the Propeaq blue light glasses. The survey included 10 items from the System Usability Scale (SUS), supplemented with 22 questions about the effect of the glasses. In total 39 questions. The study was approved by the Radboud UMC Ethics committee in Nijmegen, the Netherlands.


Average disease duration from PD diagnosis was 6.7 ± 4.6 years. Most patients (28/31, 90%) used PD medication, mainly levodopa preparations. Seven respondents (24%) used sleep medication. Most patients (23/31, 74%) used the glasses twice daily: once in the morning and once in the evening, for 30–60 minutes each time. Of the 31 patients, 23 patients (74%) reported an effect of the glasses. Of these, 16 patients (70%) reported an improvement in night-time sleep, four (13%) an improvement in daytime sleepiness, five (16%) an improvement in depressive symptoms, and four (12%) an improvement in motor functioning. Five patients (16%) reported adverse events; one patient reported transient cramps in her calves, and two other patients reported transient nausea, transient tiredness, headache, or dizziness.

All participants completed the System Usability Scale. The median score was 70.0 (1st and 3rd QT 57.5–80.0) which classifies the glasses between “ok” and “good” (Figure 1). Twenty-five patients (81%) found the glasses easy to use. A total of 26 patients (74%) had an overall positive attitude towards using Propeaq light glasses.

This feasibility study is the first in a series of studies with the aim of developing a safe and effective treatment to improve the quality of life of patients with Parkinson’s disease.

SUS score

Results research phase 1

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