Hemodynamic Effect of Dexmedetomidine Versus Magnesium Sulphate as an Adjuvant to Lidocaine in Preemptive Peribulbar Block in Patients Undergoing Dacryocystorhinostomy Under General Anesthesia

Inclusion Criteria: * Age ≥ 18 years. * Both sexes. * American Society of Anesthesiologists (ASA) physical status I or II. * Undergoing elective Dacryocystorhinostomy (DCR) surgery under general anesthesia. Exclusion Criteria: * Patients have local infection. * Allergic reaction or complications of the local anaesthesia (LA). * Coagulopathy defined as international normalized ratio (INR) \> 1.5, platelet count \< 100,000/mm³, or ongoing anticoagulant therapy not adequately discontinued. * Uncontrolled systemic disease, defined as poorly controlled hypertension \[systolic blood pressure (SBP) \> 160 mmHg\], uncontrolled diabetes mellitus (HbA1c \> 8.5%), unstable ischemic heart disease, or decompensated hepatic or renal disease. * Uncooperative patients.