Environmental factors such as noise and light have been cited as important causes of sleep deprivation in Intensive care unit (ICU) patients. Previous studies demonstrated a hyperalgesic alteration in pain perception following a controlled sleep deprivation protocol. Another studies indicated that using eye masks can improve REM sleep in healthy subjects in simulated ICU environment, and improve sleep quality in ICU patients. This study aimed to determine the effects of using eye masks on sleep and thus on pain quality in postoperative cardiac surgery patients in ICU.

Inclusion Criteria:

• (1) age ≧18 years; (2) no history of neurological or psychiatric disorders; (3) ability of patients to communicate verbally and understand the sleep questionnaires administered in the ICU; (3) length of ICU stay ≥48 hours; (4) Glasgow coma score (GCS) >8 in the first to third day. Postoperative Extubation of MV within few hour (before the time of 9 pm for postoperative patients.

Exclusion Criteria:

• Patients over age 65 were excluded from the study because of potential age-related differences in sleep. Patients reporting frequent nighttime awakenings, snoring, or chronic use of benzodiazepines or opioids were excluded because of potential confounding influences of these factors on postoperative sleep, pain, or opioid requirement.

While it is not possible to blind participants and clinical staff to the assigned interventions, the assessments will be undertaken by a researcher blinded to group allocation.