Many cataract patients after surgery found in front of the eyes of small insects, small cotton wool-like black spots or translucent “comma, question mark” in front of the eyes floating around, especially out of the door or look at the white walls more obvious. Can’t help but be a little worried, as if the preoperative did not feel much mosquito, how to do the operation but obvious, could it be that the cataract surgery is not done cleanly ah? In fact, we also have such experience in life, bright sunshine into the clean window, you can see along the beam of light in the dense dust, while in the dark place or screened room we can not see these tiny particles. These “flying mosquitoes” are actually clouding of the vitreous humor. Cataracts are like a veil over the vitreous window, blocking light from entering the eye. After removing the cataract and replacing it with a transparent and clear IOL, it is like opening the curtains of a room, the light passes through the pupil, the IOL, and reaches the retina at the bottom of the eye, and some of the “flying mosquitoes” in the vitreous body will be clearly projected and perceived. Therefore, after the surgery, our eyes are more sensitive to these subtle changes. Doctor’s tip: Mosquitoes are caused by the clouding of the vitreous behind the lens, which has nothing to do with cataracts, but with the improvement of vision after surgery, the “mosquitoes” in the field of vision will be more obvious. Patients should go to the hospital in a timely manner to review, further examination of the fundus, to determine whether some eye diseases caused by vitreous clouding, in order to early detection and early treatment.