Inclusion Criteria:  Elderly patients undergoing general anesthesia for tracheal intubation, aged ≥65 years, operation time ≥2 hours, ASA classification I-III, and postoperative hospital stay for at least one week.  Exclusion Criteria:  It is known that this study involves persons who are allergic to general anesthetics; Patients with previous eye diseases; Head and neck surgery is not conducive to measurement; Patients with preoperative MMSE score less than 24 points or dementia due to various diseases; Patients planning to undergo neurosurgery; Those who use sedatives or antipsychotics before surgery; Patients with known central nervous system diseases, such as mental illness; Patients with hearing or vision impairment and unable to communicate normally.