This study aimed to investigate whether the association between the preoperative anxiety level and emergence delirium involves EEG frontal alpha asymmetry in pediatric patients undergoing ophthalmic surgery under general anesthesia. The investigators hypothesized that EEG frontal alpha asymmetry contributes a significant portion of the preoperative anxiety - emergence delirium association in pediatric patients. Mediation analysis will be performed to estimate the relationships between preoperative anxiety of children (modified Yale Preoperative Anxiety Scale (mYPAS)), EEG frontal alpha asymmetry, and emergence delirium (Pediatric Assessment of Emergence Delirium (PAED) scale).

Inclusion Criteria:

• Children aged 2-8 year
• Children with an American Society of Anesthesiologists (ASA) physical status of I-II
• Children who are scheduled to undergo elective ophthalmological requiring general anesthesia

Exclusion Criteria:

• Emergency surgery
• Patients with developmental delays
• Patients with neurological or psychiatric diseases associated with symptoms of agitation, anxiety, attention deficit, sleep disturbances
• Patients with autism
• Patients with a recent history (within one month) of receiving general anesthesia
• Patients with congenital or genetic diseases that may influence brain development

Children aged 2-8 year with an American Society of Anesthesiologists (ASA) physical status of I-II who are undergoing elective ophthalmological requiring general anesthesia in Gangnam Severance Hospital will be eligible.