1. Refractive adjustment internal strabismus: After sufficient ciliary muscle paralysis or complete correction of hyperopic refractive error, the internal strabismus becomes orthotropic or mild internal oblique is called refractive adjustment internal strabismus. The main reason for the occurrence is the excessive collection caused by hyperopia, followed by the separation of fusion or adductor muscle reserve strength deficiency and poor binocular visual function. It accounts for about 1/4 of common internal strabismus and 1/3 of common internal strabismus in children. Main features: (1) Age of onset from 4 months to adult, most commonly occurring at about 2-3 years of age, with large changes in strabismus angle and early intermittent appearance, increasing the angle of internal strabismus when viewing near and decreasing when viewing far. (2) After sufficient ciliary muscle paralysis or complete correction of hyperopic refractive error, the internal strabismus becomes orthotropic or internal oblique. (3) The size of the strabismus angle is related to the patient’s mental status and the amount of accommodation used for near vision. (4) Mostly moderate hyperopia (+2D – +6D), with normal AC/A. (5) As the hyperopic refractive error becomes orthokeratology, the hyperopia and the angle of internal strabismus will decrease or even disappear, and some patients will develop partially adjusted internal strabismus or microstrabismus. (6) Most patients can obtain binocular vision, and as long as they use corrective glasses in time, amblyopia is less likely to occur. The basic mechanism is the abnormal relationship between regulation and regulatory assembly, which is related to high AC/A. The main features: (1) The onset of the disease is usually at the age of 1-4 years, but it is also thought to be at the age of 6 months to 3 years. (2) Binocular orthophoria when looking at distance, and internal strabismus when looking at near, especially when concentrating on fine objects or patterns. It is generally believed that this type of optic mark stimulates accommodation and is called modulated optic mark. There is no improvement in near-vision internal strabismus after sufficient paralysis of the ciliary muscle or wearing adequately corrected glasses. (3) The AC/A ratio is too high and can reach about 10 prisms/D. (4) Intraocular strabismus at the near side is reduced or disappears after wearing +3D glasses. (5) Strabismus is not related to refractive status, and patients can be nearsighted, farsighted, or orthoptic, with moderate hyperopia being more common. Most of them have binocular vision and usually do not cause strabismic amblyopia. (6) There is no uniform and effective treatment method, although wearing bifocal glasses can be inconvenient. Pupil reduction agents can be applied, which also have certain side effects.