Strabismus is divided into two categories: common strabismus and paralytic strabismus. The former is characterized by a deviated eye position to the temporal side, no eye movement disorder, and no double vision. Patients with strabismus cannot look at the target with both eyes at the same time. The following is the routine examination method of strabismus: 1. Examination of binocular visual function: (1) Domestic common use of the same visual machine to examine the three levels of binocular visual function. (2) Quantitative determination of stereo visual function, using the same visual machine stereo quantitative drawing or Yan’s random dot stereogram to determine stereo visual acuity. 2.Refractive examination: atropine paralysis ciliary muscle optometry, one is to understand the presence of amblyopia, and the other is to understand the relationship between strabismus and refraction 3.Eye position and determination of strabismus angle: to determine which type of strabismus. The size of the strabismus angle must be checked for the purpose of surgical design. 4.Ocular movement examination: to determine the function of the extraocular muscles. Eye movement examination: to determine the function of the extraocular muscles. 5.With or without compensatory head position: different head positions can help diagnose which extraocular muscle is paralyzed. 6.Check to determine the paralyzed muscle: red lens test or check with Hess screen method. 7.Traction test: (1) Estimation of postoperative diplopia and patient tolerance after preoperative retraction in orthotropic position. (2), the passive pull test: can understand whether there is mechanical pulling of extraocular muscles or muscle spasm. (3), active contraction test: to understand the function of the muscle. 8. Examination of occlusion: quantitative determination with occlusion meter. The test of collective proximal point: to help diagnose myopic fatigue. 9.AC/A ratio of modulated pooling/regulation: help to determine the relationship between strabismus and regulation and pooling.