Children with mild internal or external cryptopia do not experience eye discomfort, while those with high obliquity experience more eye discomfort with vertical cryptopia, and those with rotational cryptopia experience significant eye and general discomfort. The symptoms of cryptorchidism are also related to general health and mental status. The following symptoms often occur in cryptorchidism: 1. Headache, eye pain and photophobia often occur after prolonged vision, which is caused by eye muscle fatigue due to the continuous use of neuromuscular reserves. 2. Blurred or overlapping or serial handwriting when reading, sometimes intermittent diplopia, intermittent strabismus, and even binocular visual disorder if viewed with one eye instead of feeling clear and effortless. 3. Poor stereoscopic perception, unable to accurately determine the position and distance of spatial objects. Cryptorchidism can also present neuro-radiological symptoms, such as nausea, vomiting, insomnia, conjunctival and lid margin congestion. The dangers of strabismus are serious, starting with the cosmetic impact, which is the main motivation for making patients seek medical attention. More importantly, strabismus affects the visual function of both eyes, and in severe cases, there is no good stereopsis. Stereopsis is an advanced visual function that only humans and higher animals have, and it is one of the prerequisites for people to do fine work. Without good stereoscopic vision, people will be greatly limited in their studies and employment. Most people with strabismus also have amblyopia. As a result of long-term gaze in one eye, the other eye will have disuse vision loss or stop developing, and later, even with proper glasses, vision will not be normal. Strabismus in childhood also affects the development of the entire skeleton, such as the compensatory head position of congenital paralysis strabismus, which causes contracture of the neck muscles and pathological curvature of the spine, and asymmetrical facial development.