AIM: To observe the clinical features of paralytic strabismus and analyze its etiology.

METHODS: Eighty-nine cases(97 eyes)were diagnosed with paralytic strabismus and recruited in this study in the Department of Ophthalmology, the Fourth Affiliated Hospital, China Medical University between July 2008 and February 2013. The clinical data were recorded including the general and ophthalmic history, symptom, visual acuity, fundus, pupil, eyelid, visual field, eye movement, synoptophore, acting countervail head, ultrasound of eyeball and ocular muscle, color Doppler ultrasonography of the carotid artery, orbital computed tomography(CT), brain magnetic resonance imaging(MRI), blood biochemistry and immunologic tests.

RESULTS: The medical history disclosed that among these cases, hypertension in 36 cases, diabetic mellitus in 28 cases, hyperlipidemia in 19 cases, heart diseases in 17 cases, ischemic cerebrovascular disease in 12 cases and hyperthyroidism in 3 cases. Symptoms included vertigo in 47 cases and binocular temporal amaurosis in 36 cases. The horizontal restriction was manifested in 38 cases 45 eyes, vertical restriction in 42 cases with 42 eyes, and horizontal-and-vertical restriction in 9 cases with 10 eyes.

CONCLUSION: Brain vascular ischemic disease is one of the top reasons causing paralytic strabismus. Systemic disease history was found in a high proportion of the cases. It is of great essence to detect the life-threatening ischemia of vertebrobasilar artery system and take priority for treatment.