If there is a spider’s web change in the eye, if the dark shadows in front of the eye are floating, consider vitreous opacities to be the cause. If the black shadow in front of the eyes is fixed, it is considered that there is a problem with the refractive interstitium, such as keratitis, clouding of the lens, retinal optic nerve, and macular lesion. Therefore, if spider web changes are found, it is best to visit the ophthalmology clinic in a timely manner and undergo routine eye examination, dilated pupil examination, fundus examination, ultrasound of the eye and macular OCT examination. After the diagnosis is confirmed, timely treatment is needed. If the sudden appearance of vitreous clouding may be due to eye trauma, or posterior vitreous detachment, or high myopia or uveitis, if there is also a flashing sensation, you need to be alert to the possibility of retinal detachment. If it is caused by keratitis, cataract or macular lesion in the fundus, it is usually accompanied by some degree of vision loss.