Primary foraminal retinal detachment is defined as a retinal detachment that occurs when liquefied vitreous body enters the retina between the retinal neuroepithelium and the pigment epithelium through the retinal fissure. OVERVIEW: Also known as Eales’ disease, it occurs in male patients between the ages of 20 and 40, often with sequential onset in both eyes. It is one of the common causes of vitreous hemorrhage in young men, second only to ocular trauma, and is characterized by recurrent retinal and vitreous hemorrhage in both eyes, initially in the peripheral part of the retina, and often asymptomatic when the amount of hemorrhage is small, and some patients feel a mild blurring of vision or symptoms similar to flying mosquito phantom vision within the first few days, and if detected early, fundus fluorescent angiography and laser are very important in the diagnosis and treatment of the disease, and can often be restored to better vision. If detected early, fundus fluorescence angiography and laser are very important in the diagnosis and treatment of this disease, and good vision can often be restored. When there is a lot of hemorrhage, the blood enters the vitreous humor, and the patient will only feel a black shadow floating in front of his eyes. When the disease further develops and a large amount of vitreous hemorrhage occurs, the visual acuity decreases sharply, and even causes retinal detachment and blindness. If the vitreous hemorrhage is not absorbed for a long time or is complicated by retinal detachment, it needs to be treated by vitrectomy. Etiology: The etiology of this disease is diverse. The first consideration of tuberculosis, most of the tuberculin-induced type III anaphylactic reaction, such cases of systemic and ophthalmic treatment are not active tuberculosis, or only old lesions (such as lungs, pulmonary portal calcification foci), tuberculin skin test is strongly positive, and can induce a focal reaction, so that retinal vein inflammation and vitreous hemorrhage suddenly exacerbated. Thromboembolic vasculitis may invade retinal vessels, resulting in retinal vitreous hemorrhage. Septic foci, such as chronic tonsillitis, dental caries, and skin abscesses, are also relatively common causes of the disease. In addition, diabetes mellitus, ascariasis, syphilis, tuberculosis, Behcet’s syndrome, etc., have also been reported to cause this disease. Clinical manifestations: Visual function is impaired, depending on the size of the affected vessel, the amount of bleeding and the location. If the lesion is located in the peripheral part of the fundus of the blood vessels, hemorrhage is not much, the patient has no conscious symptoms or only mosquito; when the lesion is located in the larger veins, hemorrhage, break through the inner boundary membrane into the vitreous body, or hemorrhage, although less and is located in the macula, the visual acuity suddenly decreased, and in severe cases, it can be suddenly decreased to the front of the eye index, manual, and even the sense of light. Fundus examination can only be seen when the retinal hemorrhage has not entered the vitreous body or when there is a small amount of blood in the vitreous body. Retinal vein changes are commonly accompanied by white sheaths on the walls of the tubes, flame-like or sheet-like hemorrhages in the vicinity, which are interspersed with grayish-white exudate spots with blurred boundaries, vein branches are segmented or the whole blood vessel is whitelined, and neovascularization or anastomoses can be seen in the vicinity, and there are scarring whitish and pigmented patches. Dark red bloody turbidity in the vitreous. Vitreous blood accumulation in the first 1 or 2 episodes is absorbed quickly, and has largely disappeared within a few weeks of the onset of the disease, and the vision improves. If there is no damage to the macula, it can return to normal or near normal. The disease is easy to recur, after many times of repetition, the vitreous blood is more and more difficult to be absorbed, and finally mechanized, manifested as different ranges and different forms of mechanized membrane. There may be neovascularization on the mechanized membrane, and the weak wall of neovascularization is easy to rupture, which increases the chance of recurrent bleeding. In addition, the contraction of the mechanized membrane can easily lead to traction retinal detachment. Diagnosis: The disease mostly involves both eyes. However, the severity of the disease in both eyes and the frequency of recurrence is not consistent, one eye has a large amount of vitreous hemorrhage fundus can not be examined, regardless of whether the other eye has no symptoms, the pupil should be fully dilated after examination of the fundus. If in the peripheral part of the fundus, one or several small branches of the veins are seen to be full, twisted, with bleeding or oozing foci nearby, and white sheaths or turbidity on the walls of the veins, it can be used as a clinical diagnosis. As for the etiology, it should be clarified as much as possible so that the treatment can be targeted. A thorough physical examination and necessary laboratory tests, such as chest radiography or radiographs, should be performed to check for tuberculosis or nodular disease. Skin, oral, ear, nose and throat examination for septic foci or shallow ulcers, anti-“O”, syphilis rapid plasma reactive element test, blood picture, stool routine. Since most of the disease is caused by tuberculosis metaplasia, the tuberculin test is often done clinically. As long as the patient has a past history of tuberculosis, or see systemic inactive tuberculosis foci (such as pulmonary hilar or pulmonary calcification foci, etc.), and after the examination and can not be found by other suspected etiology, can be deduced accordingly. Treatment: The treatment of this disease can be roughly divided into two stages. In the first stage, i.e., after the sudden onset of hemorrhage, the patient should be advised to avoid strong activities and to try to lie in a semi-recumbent position with a high pillow. Give more explanation to eliminate the anxiety and fear arising from the sharp decline in vision. And give hemostatic drugs, vitamin K, C, Lutin and calcium. Fluorescence angiography of the fundus is performed after the retina can be seen, and retinal laser treatment is performed as appropriate. Generally speaking, the first 1 to 2 times of vitreous hemorrhage, can be self-absorbed relatively quickly. But after repeated episodes, it is difficult to absorb, old vitreous hemorrhage, often need surgery. If the vitreous hemorrhage is not absorbed for a long time or is complicated by retinal detachment, it needs to be treated by vitrectomy. Prognosis: The visual prognosis of this disease depends on whether the macula is damaged or not, and whether traction retinal detachment occurs or not. The prognosis is generally poorer in those with a lot of vitreous blood, or recurrent recurrences. However, as long as the macula is undamaged, vision can be restored to its original level or close to it during the period between the absorption of the accumulated blood and the lesion veins. On the contrary, if the macula is involved, vision will be irreversibly impaired even if there is little hemorrhage or only the first episode. Vitreous hemorrhage, especially after repeated episodes of vitreous hemorrhage, often not easy to disappear, and finally form proliferative vitreoretinopathy, or connective tissue contraction, causing traction retinal detachment, the prognosis is poor. Prevention: In addition to active treatment, it is necessary to remove the cause of the disease. Avoid emotional overstimulation, mental and physical fatigue, pay attention to daily living, abstain from sexual desire, eat less spicy fried products, quit smoking and alcohol. If one eye is already sick, the other eye should be examined.