The main reason for dilating the pupil for one month after vitrectomy is to prevent the pupil from sticking together when the pupil is narrowed due to inflammation after the operation. Glass excision is called vitrectomy, belongs to the inner eye surgery, often accompanied by intraocular inflammation, need routine application of antibiotics such as levofloxacin 3 to 5 days anti-infection, pupil dilator such as atropine, tropicamide drops, etc., in order to prevent infection, dilate the pupil, to prevent the pupil from narrowing the pupil and the occurrence of pupillary adhesion. Atropine pupil dilation utility lasts about 2 to 3 weeks, but patients need to pay attention to the topical use of eye drops, can be used to press the inner corner of the eye with a finger, to prevent the drug through the tear duct into the nasal cavity, absorbed by the blood caused by systemic reactions such as dry mouth, headache, panic and other uncomfortable symptoms. It is recommended that patients follow the doctor’s instructions for care after vitrectomy, regular checkups, and timely consultation when discomfort occurs.