In short, "heavy water" is a soft instrument in ophthalmic surgery; "Silicone oil is a temporary filler in ophthalmic surgery, which is further elaborated as follows: 1. The so-called "heavy water" in ophthalmology is not heavy water (deuterated water) used for deceleration of nuclear reactors. In fact, it is a purified perfluorocarbon liquid with higher specific gravity than water, transparency, certain surface tension and no toxicity after short-term application. Based on the above characteristics, the proper use of heavy water in the operation can help the operator to release subretinal fluid smoothly, detach from the retina smoothly and stop bleeding by compression. The floating of lens nucleus and intraocular foreign bodies in the vitreous cavity is realized, and it is convenient to take out sharp knives and scissors under the microscope. Heavy water is called "soft instrument" because of its versatility and colorless and amorphous shape. As mentioned above, in clinical practice, complicated retinal detachment, intraocular foreign bodies caused by eye trauma, or lens nucleus falling into vitreous cavity or bleeding during cataract surgery are the keys to determine the success of the operation. Obviously, the retention of heavy water in the eye after operation will cause a series of eye complications, which must be completely completed at the end of the operation. . . . . . In the field of ophthalmology, silicone oil is only used for complicated retinal detachment and severe eye trauma. Objective To give sustained and effective top pressure to the retina that has been reset during operation through temporary silicone oil intraocular filling, so as to prevent recurrent retinal detachment. Silicone oil filling in severe ocular trauma can maintain the stability of intraocular pressure to some extent. Silicone oil that preserves the appearance of eyeball can not completely replace the function of normal vitreous body. After filling the vitreous cavity for a long time, it may also lead to many serious eye complications. Generally, three to six months after the first silicone oil filling operation, the omentum recovered well and the intraocular pressure was normal, so it should be taken out again in time.