Dry eyes is a disease caused by the insufficient quantity of tears of tear film in the cornea, leading the conjunctiva and epithele of cornea to function abnormally. Dry eye is a chronic disease and there are several reasons to account for it. Firstly, the physiological reasons such as advanced age, lack of sleep and psychentonia can lead to the reducing tears. Secondly, medicines which bring high blood pressure down or stabilizer have an influence on tears. Thirdly, environment such as arid room could give rise to the increasing evaporation of tears. Fourthly, spending long time manipulating computer, driving, reading without blinking your eyes could cause dry eyes. Fifthly, using antibiotics for a long time makes the flora lose balance and give rise to dry eyes. When getting dry eyes, you can use eyedrops to keep your eyes moist.