Suddenly half of the eye can not be seen, mainly seen in the following cases: 1, pore source retinal detachment, trauma or high myopia caused by retinal fissure, when the fluid in the vitreous cavity from the fissure, a large number of entering the retina under the retina, it will cause the retinal neuroepithelial layer from the wall of the eye. When the retinal detachment is large enough, it causes half of the visual field to be defective, resulting in a situation where half of the eye is suddenly invisible. Depending on the patient’s age and the location of the fissure, you can choose to do extra-scleral compression surgery, or vitrectomy for treatment. 2. Retinal branch artery obstruction, generally acute onset, after the branch artery blood vessel supplying the retina is obstructed, the retinal function is sharply impaired, making the visual field defective and appearing Suddenly half of the vision is not visible. It is one of the clinical ophthalmic emergencies and requires emergency resuscitation, oxygenation, sublingual nitroglycerin, IOP lowering, thrombolysis and other therapeutic measures.