Displacement of the IOL can produce symptoms such as eye pain, headache, even nausea and vomiting, loss of vision and double vision. An IOL is a precision instrument that is surgically implanted in the eye to replace the original lens. Displacement of the IOL will affect the circulation of the aqueous humor in the eye, resulting in an increase in intraocular pressure, which will cause glaucoma symptoms such as eye pain and headache, and in severe cases, affect the optic nerve. As an important alternative refractive medium in the eye, the IOL allows light rays to converge on the retina and be recognized by photoreceptor cells, producing a clear image. Once displaced, it can lead to vision loss and blurred vision. Dislocation of the IOL also produces abnormal visual function phenomena such as diplopia and confusion. Since light cannot be focused on the retina, part of the light rays are refracted through the IOL, and part of them go directly into the eye, resulting in double vision. Once the IOL is displaced, it is recommended to go to the hospital immediately for treatment to improve the above symptoms under the guidance of the doctor.