In addition to flushing the eye surface and removing microorganisms and foreign bodies, tears also form a tear film to protect the cornea and together maintain a good refractive state. The tear film is an important structure on the surface of the eye, and although it is invisible to the naked eye, he exists there. An unstable tear film is prone to rupture, causing discomfort such as dry eyes, foreign body sensation, tingling, photophobia, tearing, blurred vision, etc., which means that you will suffer from dry eyes. Tear film is a composite membrane on the surface of the cornea, the most surface for the lipid layer, we all know that oil is lighter than water, so the surface of the tears floating a layer of oil film, so as to prevent tears from evaporating too quickly, this layer is not complete tears are easy to evaporate, resulting in tear film instability; central for the aqueous layer, the aqueous layer and the mucin layer below there is no obvious boundary, just to elaborate and proposed, there are also proposed aqueous protein layer, the upper The bottom is the mucin layer, which is attached to the cilia of the corneal epithelium and plays a stabilizing role in the aqueous layer and a key role in maintaining the stability of the tear film. Corneal epithelial cell cilia also play an important role in the stability of the tear film, after eye surgery, or long-term frequent use of eye drops containing preservatives, corneal epithelial cell cilia are damaged, but also prone to tear film stability decline. Currently, the more commonly used artificial tear drops include chondroitin sulfate eye drops, sodium glassate eye drops, carbomer eye drops, and hydroxypropylmethylcellulose eye drops. Single-component eye drops can hardly simulate the mechanism of tear film, only that such drops are viscous and attach to the eye surface for a longer period of time, which can relieve various discomforts of dry eyes, and the viscous drops will be more or less mushy and not so refreshing and natural. Therefore, some compounded artificial tears, such as polyethylene glycol propylene glycol eye drops and dextran 70 glycerin eye drops, are also listed. Current eye drops are added with preservatives to ensure that the quality of the drops can be maintained for a period of time after opening, but the long-term use of preservatives also damages the eye surface, so patients with long-term frequent eye drops also have dry eyes. In order to solve this problem, the current method is to change the packaging of the drops into a daily pack, one eye drop is enough for one day, and it is effective for use on the same day, but should be discarded on the next day. There is also a change in the current widely used preservative benzalkonium chloride for another large molecule substance instead, although the manufacturer claims that this large molecule will not damage the eye surface, but I consider the whole body after absorption there is no harm not mentioned, can destroy bacteria without damaging human cells? There are daywear optional, with daywear why not.