Inclusion Criteria:  Adult patients Aged 21- 60 years American Society of Anesthesiologists class (ASA) I to III presented for elective strabismus surgery under peribulbar anesthesia.  Exclusion Criteria:  Patient refusal to participate. uncooperative patient. Neurological disorders. Psychological disorders Suspected or diagnosed coagulopathy. Known allergy to the used medications. Ocular infection Co-existing glaucoma