Progressive visual impairment is more common in ametropia, primary open-angle glaucoma, cataract, hereditary and metabolic diseases of optic nerve and retina, and less common in orbital and intracranial masses. Intracranial arachnoid cysts are usually asymptomatic benign congenital lesions with a small number of visual impairments. The absence of the bone wall of the optic canal was seen in normal subjects with good gasification of the posterior ethmoid sinus and sphenoid sinus. In this case report we describe a 59-year-old man with a left temporal arachnoid cyst and a defect of the bone wall of the optic canal complained of left visual field defect and blurred vision for more than one year. The mechanism of visual dysfunction was analyzed by collecting the patient’s medical history, imaging data and the results of visual function examination.