Ophthalmic Surgery

This study aims to evaluate whether a lower dose of ketamine (0.5 mg/kg IV) may be as effective as a higher dose (0.75 mg/kg IV) in reducing oculocardiac reflex (OCR) incidence in adult patients undergoing ophthalmic surgery.

The goal of this clinical trial is to learn if Anrikefon works as well as nalbuphine to control postoperative pain in adults undergoing ophthalmic surgery under general anesthesia. It will also learn about the safety and recovery outcomes of using Anrikefon. The main questions it aims to answer are: * Does Anrikefon provide pain relief that is not inferior to nalbuphine after ophthalmic surgery? * Does Anrikefon cause fewer central side effects, such as sedation or dizziness, compared with nalbuphine? * Does Anrikefon help patients recover and get discharged faster after day-surgery procedures? Researchers will compare Anrikefon to nalbuphine to see if Anrikefon can offer effective and safer perioperative analgesia for ophthalmic day-surgery patients. Participants will: * Receive either an intravenous dose of Anrikefon or nalbuphine during surgery. * Be monitored for pain scores, side effects, and recovery parameters after surgery. * Complete follow-up assessments.