Dark shadows in the eyes of the elderly may be caused by corneal foreign bodies, vitreous clouding, retinal detachment, fundus hemorrhage and so on. 1. Corneal foreign body: if there is a foreign body in the cornea and the foreign body is just in the center of the vision, there will be a dark shadow in the eye. 2. Vitreous clouding: the dark shadow of the eye moves with the line of sight and does not affect vision, mostly due to vitreous liquefaction caused by aging, vitreous clouding, which is also known as flying mosquito syndrome. 3. Retinal detachment: when the retina is detached, there are black shadows and flashing sensation. 4. Fundus hemorrhage: the sudden appearance of black shadows in front of the eyes of the elderly, may also be fundus hemorrhage. Elderly people with dark shadows in the eyes must go to the hospital in time, after a clear diagnosis and active treatment, so as not to delay the condition.