Cluster headache is a primary headache. The chronic form of the disease is often difficult to treat. It is now considered a chronobiological disease. This chronobiological character is based on clinical, biological and radiological arguments.

This study focuses on the use of light therapy in cluster headache. Light therapy has already been used in the treatment of other chronobiological diseases, such as seasonal depression, but also recently in the therapy of other primary headaches (such as migraine). Its aim is to re-adjust chronobiological rhythms, and it therefore seems worth testing in the chronic form of cluster headache.

Light therapy is delivered to the patient using a consumer electronics device.The main objective is to evaluate the prophylactic efficacy of light therapy in patients with chronic cluster headache.

Inclusion Criteria:

• Male or female, of 18 years years old or more;
• Diagnosis of chronic cluster headache according to ICHD-3 criteria;
• Number of seizures during baseline equal to at least 24;
• Stability of prophylactic treatment for at least 1 month and commitment not to change it for the duration of the study;
• Patient affiliated to the French social security system.
• Patient who understands and speaks French correctly;
• Patient who has given free and informed written consent.

Exclusion Criteria:

• Contraindication to the use of light therapy: use of a photosensitizing treatment;
• Ophthalmological history: cataract, macular degeneration, glaucoma, retinitis pigmentosa;
• Patients who work at night;
• Other neurological, psychiatric or developmental pathologies considered incompatible with the study;
• Background treatment of cluster headache with melatonin;
• Persons protected by articles L1121-5, L1121-6 and L1121-8 of the French Public Health Code (pregnant or breast-feeding women, persons deprived of their liberty by judicial decision, socially vulnerable persons, adults incapable or unable to express their consent).