The goal of this clinical trial is to assess the feasibility of conducting a clinical trial of the use of blue-blocking glasses among patients with a type1 bipolar disorder, experiencing a manic episode. The feasibility criteria include: recruitment rates, participation rates, adherence to the research protocol, the material feasibility of the study. Feasibility criteria will be assessed at the end of the study period. The investigators also want to assess patients' acceptability regarding the use of blue-blocking glasses during a manic episode, using self-reported satisfaction criteria. Those criteria will be monitored at the end of participation period for each patient (7 days after inclusion). In addition, the study will evaluate the impact of the use of blue-blocking glasses on the severity of manic symptoms, sleeping pattern (quality of sleep, sleep latency, night wake, etc.), global functioning, and on suicidal ideations. Those indicators will be assessed at day 0 (inclusion), day 3 and day 7, using validated questionnaires and actimetry data. The study is presented to all patients over 18 years old, with type 1 bipolar disorder, presenting a manic episode, hospitalised in an adult psychiatric ward of Bichat Hospital (GHU Paris). Patients' participation duration is of 7 days after inclusion.