Inclusion Criteria:  The patients planned to perform a unilateral strabismus surgery Age: 20-60 years American Society of Anesthesiologists class I and II  Exclusion Criteria:  patients under the age of 20 Patients have systemic or bleeding disorders Patients with ocular or neurological problems, mental retardation, deafness, or dementia patients who disincline to participate in the study will be excluded from the study