Optic nerve double vision does not exist in clinical practice, but is often expressed as double vision. Monocular double vision may be associated with refractive error, corneal lesions, etc. Double vision may be associated with lesions of the nerves or muscles that innervate the movement of the eyeballs, which are commonly seen in clinical conditions such as visual fatigue, paralytic strabismus, cataracts, subluxation of the lens, ocular injuries, brain lesions, and diabetes mellitus. Myopia and other refractive error factors, corneal edema, corneal inflammation, can lead to monocular vision symptoms. Prolonged close reading can lead to visual fatigue and double vision. Paralysis of extraocular muscles leads to strabismus with double vision. Cataracts of varying severity in both eyes and subluxation of the lens, which causes some light to reach the retina without refraction, can cause double vision. Ocular trauma resulting in orbital fracture, muscle damage, etc., and brain lesions such as cerebral thrombosis causing abnormal intracranial nerve function can also cause double vision. In addition, diabetes mellitus may cause damage to the nerves innervating eye movement such as the motor nerve, resulting in double vision. It is recommended that the patient go to the hospital in time to have the cause of the problem clarified through examination.