A shadow in front of the eye may be caused by vitreous clouding, retinal hemorrhage, or ischemic optic neuropathy. 1. Vitreous clouding: This may cause a cloudy substance to appear in the vitreous cavity, and light will project the shadow of the cloudy substance onto the retina, which may appear as if there is a shadow in front of the eye. 2. Retinal hemorrhage: Diabetic retinopathy, hypertensive retinopathy and other diseases lead to retinal hemorrhage, the retinal hemorrhage will obscure the light, which will lead to the situation that seems to have a shadow in front of the eyes. 3. Ischemic optic neuropathy: the optic nerve blood vessels are blocked due to ischemic optic neuropathy, causing optic nerve conduction dysfunction, resulting in part of the visual information obtained by the retina not being able to be transmitted to the visual center, which results in the condition of having a shadow in front of the eyes. It is recommended to consult a doctor for diagnosis and treatment.