Non common strabismus: also known as paralytic strabismus, it is caused by the paralysis or incomplete paralysis of the extraocular muscle due to the lesions of the nerve nucleus, nerve or extraocular muscle that dominate the extraocular muscle.

Clinical manifestations: the affected eyeball deviates in the opposite direction of the paralytic muscle, and the target image falls on the non corresponding point of the retina of both eyes, resulting in diplopia and confusion. In order to avoid binocular visual abnormalities caused by insufficient function of extraocular muscles, the patient adopts compensatory head position. The consequences of extraocular muscle paralysis are spasmodic contraction of the antagonistic muscle, excessive contraction of the synergetic muscle of the contralateral eye, and inhibitory paralysis of the antagonistic muscle of the contralateral eye. The second oblique angle is more than 5 △ greater than the first oblique angle.

Treatment principle: 

if the deflection angle is less than 15 △ and the prism correction effect is good, if the prism correction is still ineffective for more than half a year, surgery should be considered.

Non concomitant strabismus is the abnormality of the extraocular muscle of the eye, the medial strabismus is the paralysis of the lateral rectus muscle, and the lateral strabismus is the abnormality of the medial rectus muscle.