The goal of this clinical trials to study and compare the effects of "desflurane with remifentanil anesthesia (study group)" and "sevoflurane with remifentanil anesthesia (control group)" for elective fundus surgery anesthesia. The main question it aims to answer are the characteristics of desflurane anesthesia in patients undergoing fundus surgery and to provide universal guidance for clinical application.

Inclusion Criteria:

1. ASA I-II, patients aged 18-65 years old;
2. Fundus surgery to be performed under general anesthesia ;
3. The expected duration of surgery is about 30-120 min ;
4. BMI: 18-30 kg/m2 ;
5. Those who signed the informed consent form and volunteered to participate in this trial

Exclusion Criteria:

1. Patients with known or suspected genetic susceptibility to malignant hyperthermia;
2. Patients with history of asthma;
3. Patients with severe heart diseases (NYHA ≥ III, severe arrhythmia, etc.) and cerebral or pulmonary diseases, liver or kidney dysfunction; or with unstable vital signs;
4. Patients with history of long-term narcotic analgesics application, including sedative and antidepressant drugs;
5. Patients with history of psychotropic drug abuse within 3 months;
6. Patients with long-term alcohol abuse;
7. People with mental disorder and unable to communicate normally;