The mosaic of the eye indicates a black shadow block in front of the eye, usually seen in monocular onset associated with ocular disease, commonly seen in corneal disease, seen in the central area of the corneal foreign body, keratitis, corneal opacification, clouding of the central lens area, various inflammatory or hemorrhagic causes, resulting in a large vitreous clouding will affect the central vision, because the clouding is unevenly manifested as a mosaic-like block and with fluttering. Fundus diseases commonly include macular lesions, such as macular hemorrhage from various causes, namely age-related macular degeneration, pathological myopia, hypertension, diabetes, toxemia of pregnancy, etc., optic neuritis or retrobulbar optic neuritis, which can also appear as black shadows in front of the eyes, and the sense of black shadows obscuring in front of the eyes requires detailed fundus examination in ophthalmology.