Dexmedetomidine versus Fentanyl as adjuvants to local anesthetic mixture in peribulbar block for retinal surgery, a randomized prospective study.

INTERVENTION: GROUP D GROUP F CONDITION: ; Eye Diseases ; Surgery ; local anesthetic mixture in peribulbar block for retinal surgery, ; Anaesthesia Anaesthesia Eye Diseases local anesthetic mixture in peribulbar block for retinal surgery, Surgery PRIMARY OUTCOME: ¿ Effectiveness of the block sensory block The duration of sensory block and the duration of motor block SECONDARY OUTCOME: ¿ Heart rate, mean arterial blood pressure and sp02 ¿ Sedation levels will be assessed by Ramsay Sedation Score ¿ Visual analogue scale will be used to assess the patients¿ level of pain The total paracetamol consumption (mg) and the number of patients (%) requiring naluphin as rescue analgesia medication, the time of first request for analgesic will be recorded. INCLUSION CRITERIA: , ASA I‐III, aged 40‐80 years old, scheduled for retinal surgery under local anesthesia will be included in the study