survey of paralytic strabismus: a regional survay

one of the important causes of strabismus in all ages is extraocular muscles paralysis due to 3rd, 4th and 6th cerebral nerve palsies. exact and on-time treatment can result in improvement of deviation, am-blyopia and abnormal head posture. we studied epidemiological characteristics of extraocular muscles paralysis. this retrospective study performed on 131 subjects (58% male). records of patients with diagnosis of paralytic strabismus referred to private clinics between 1995 and 2005 were studied and their demographic data and clinical characters were extracted and evaluated. average age of patients was 23 years old. unilateral involvement was seen in 94% of cases. the types of paralysis were 4th nerve (70.2%), 6th nerve (17.8%), 3rd nerve (12%) and all nerves palsy (3,4 nerves) (2.2%). the most common causes of nerve injury were congenital (62.5%), trauma (19.8%), vascular (3.8%), iatrogenic (3%), tumor and aneurysm (2.2%) and miscellaneous (9%). the most common causes in 3rd nerve palsy were trauma (40%), congenital (20%), iatrogenic (10%), aneurysm (5%), vascular (5%) and miscellaneous (10%). pupilary involvement was seen in 55% of cases and complete form of 3th nerve in 50% of patients. the most common causes in 4th nerve palsy were congenital (81.5%), traumatic (8.5%) and miscellaneous (10%). in 6th nerve palsy, the most common causes were trauma (50%), vascular (13.6%), congenital (9%). this study indicates that the most common type of palsy is 4th, 6th and 3rd nerves and the most common causes are congenital and trauma.