Vitreous hemorrhage occurs when blood leaks into the space between the lens and the retina of the eye (vitreous body) which may be caused by retinal tears, retinal neovascularization and bleeding of vessels in the vitreous body.
Patients with vitreous hemorrhage commonly present with painless unilateral floaters with or without visual loss. Mild hemorrhage is associated with floaters, cobwebs, shadows, a red hue or haze. Severe hemorrhage diminishes visual clarity or causes scotomas which is worse in the morning time due to blood settling on the macula. Physicians should try to identify the underlying cause by determining whether patients have a history of trauma, diabetes, ocular surgery, high myopia, sickle cell anemia, leukemia and carotid artery disease. Examination should consist of indirect ophthalmoscopy with scleral depression and gonioscopy to assess neovascularization. If blood obscures view of posterior pole, intraocular pressure (IOP) and B-scan ultrasonography should be performed. Etiology of vitreous hemorrhage may be determined through dilated examination of contralateral eye.
Vitreous hemorrhage is easily detected using a microscope with a split beam set off-axis on highest magnification to identify red blood cells just posterior to the lens. In some cases, where view of the retina is possible, the source of the vitreous hemorrhage can be identified. Preretinal vitreous hemorrhages are found in the subhyaloid space and are often boat-shaped. Dispered vitreous hemorrhage is less defined and varies from a few red blood cells in the body of the vitreous to total covering of the posterior pole.
Physicians should try to determine etiology by asking patients if they have a history of trauma, diabetes, ocular surgery, high myopia, sickle cell anemia, leukemia and carotid artery disease. Examination should consist of indirect ophthalmoscopy with scleral depression and gonioscopy to assess neovascularization. Vitreous hemorrhage is easily identified using a microscope with a split beam set off-axis on highest magnification to identify red blood cells just posterior to the lens. In cases where view of the retina is possible the source of the vitreous hemorrhage should be identified. If the fundus is concealed by blood, corneal opacification or cataract ultrasonography must be performed, which will reveal if the retina is attached, an intraocular foreign body is present and if a posterior vitreous detachment has occurred. Previous studies have shown that using ultrasonography physicians may inappropriately identify a vitreous hemorrhage as a retinal detachment. To distinguish between vitreous hemorrhage and retinal detachment it is important to know that 1) retinal detachment can be followed back to the optic disk, 2) vitreous hemorrhages remain horizontal upon side to side eye movement and 3) vitreous hemorrhages are often located in the middle of the posterior eye. Acute vitreous hemorrhages may not appear organized or structured at first, however, over time these structures may become organized into a linear structure.
Effective treatment will address the underlying cause, therefore, it is important to determine the cause of vitreous hemorrhage if possible  . Patients often require only outpatient treatment. Hospitalization is rarely necessary for vitreous hemorrhage, although in cases with severe hyphema in unreliable or noncompliant patients close observation in a hospital setting is needed. Patients should get plenty of bed rest with the head elevated 30-45º and occasional bilateral patching to allow examination of the superior fundus once blood settles. Anticlotting drugs such as aspirin should be avoided. Surgery to address the underlying cause of vitreous hemorrhage should be performed as soon as possible for best results. Types of surgeries may include; closure of retinal breaks or treatment of retinal vascular disease with laser photocoagulation or cryotherapy, reattachment surgery of detached retinas or surgical removal of vitreous blood. Vitreous blood should be removed with surgery if;
Prognosis of vitreous hemorrhage is highly variable and depends on underlying cause and extent of hemorrhage. Typically, patients with an established vitreous hemorrhage that hasn’t damaged the retina maintain good vision. Long-standing blood in the vitreous produces ghost cells which can block the trabecular meshwork and subsequently cause vitreous hemorrhage-induced glaucoma. The trabecular meshwork may be blocked by red blood cell debris (hemolytic glaucoma) or the endothelial cells of the trabecular meshwork may be damaged by iron released from red blood cells (hemosiderotic glaucoma). Hemosiderotic glaucoma is usually a result of recurrent vitreous hemorrhages over many years. A long-standing vitreous hemorrhage in children younger than two years of age may cause myopic shift and amblyopia. The risk of vitreous hemorrhage in high myopic individuals increases due to a higher incidence of retinal tears and detachment. Patients with vitreous hemorrhage caused by diabetic retinopathy or age-related macular degeneration typically have a worse prognosis than patients whose vitreous hemorrhage arises from posterior vitreous detachment.
Risk factors for developing vitreous hemorrhage include diabetic retinopathy, retinal vein or artery occlusion, retinal tears with or without detachment and posterior vitreous detachment. Patients with severe myopia that have retinal tears are at a much higher risk for developing vitreous hemorrhage. The leading cause of vitreous hemorrhage in children and infants is trauma, including shaken baby syndrome   .
In adults, the most common cause of vitreous hemorrhage is diabetic retinopathy which accounts for 31.5-54% of cases in the United States (US), 19.1% in Sweden and 6% in London . Vitreous hemorrhage may also be caused by retinal tear, rhegmatogenous retinal detachment, retinal neovascularization, sickle cell retinopathy, posterior vitreous detachment with retinal vascular tear, macroaneurysm, macular degeneration, terson syndrome and trauma. In younger people, the most common cause of vitreous hemorrhage is trauma, including shaken baby syndrome  . Children and adults with congenital retinoschisis and pars planitis may also develop vitreous hemorrhage due to their conditions. The most common causes of vitreous hemorrhage in blacks are diabetes and sickle cell disease and in elderly whites the most common causes are retinal tears, retinal vein occlusion and diabetic retinopathy. 6.4-18% of vitreous hemorrhages are due to rare causes and from 2-7.6% of cases no specific cause may be identified. The prevalence and demographic of this disease parallels very closely the prevalence of the causative diseases listed above.
There are three main classifications of vitreous hemorrhage which include; 1) abnormal vessels (prone to bleeding), 2) stress induced vessel rupture or 3) blood from an adjacent source. In diseases such as diabetic retinopathy, sickle cell retinopathy, retinal vein occlusion or ocular ischemic syndrome ischemia occurs, leading to neovascularization which results in abnormal retinal vessels that are prone to bleeding. The mechanism for this is the release of angiogenic factors, such as vascular endothelial growth factor (VEGF), due to low oxygen which induces neovascularization of the retina with blood vessels that lack tight junctions and are therefore leaky. Also, contraction of these newly formed blood vessels provides additional stress that can rupture these fragile vessels. High levels of mechanical force can induce the rupture of normal vessels leading to hemorrhage. Conditions that cause vitreous traction on the retinal blood vessels, such as posterior vitreous detachment, may provide enough stress to rupture retinal blood vessels, which can occur with or without a retinal tear or detachment. In these cases, clinicians should be aware that the possibility of retinal break is rather high (70-95%). In younger individuals, blunt or perforating trauma may directly damage normal blood vessels causing vitreous hemorrhage. Certain pathologies affecting tissue adjacent to the vitreous can cause vitreous hemorrhage by extending through the internal limiting membrane of the vitreous. This may occur due to hemorrhage from retinal macroaneurysms, tumors or chorodial neovascularization. In Terson’s syndrome, which is a rare cause of vitreous hemorrhage, subarachnoid hemorrhage leads to a rise in intracranial pressure which causes retinal veins to rupture leading to extravasation of blood into the vitreous.
Vitreous hemorrhage can cause a number of complications including hemosiderosis bulbi with photoreceptor toxicity, glaucoma, severe floaters and myopic shift (in infants).
Risk factors for systemic vascular diseases, including diabetes and hypertension, should be controlled. Smoking is also discouraged to decrease risk of vitreous hemorrhage. Patients at high risk for retinopathy should receive regular dilated fundus exams. Eye trauma should be avoided by wearing eye protection while performing certain activities, such as metal work, firing guns and playing sports with small quickly moving balls (eg. racquetball).
The vitreous body (or vitreous) is the space between lens and the retina that is filled with a gel-like substance, composed of 99% water and 1% collagen and hyaluronic acid, known as vitreous humor. This structure takes up 80% of the eye which is approximately 4 mL in adults. When blood is found in this area, which is anterior to the zonular fibers and posterior lens capsule, lateral to the nonpigmented epithelium of the ciliary body and posterior to the lamina limitans interna of the eye, it is referred to as a vitreous hemorrhage. Since blood within the vitreous cannot be easily distinguished from blood in the subinternal limiting membrane and the preretinal area, all of these conditions are considered different types of vitreous hemorrhage    .
Vitreous hemorrhage is blood in the portion of the eye located between the lens and the retina (the vitreous body) which may cause sudden changes in vision. This condition may be caused by a burst blood vessel in the eye, trauma to the eye, a retinal tear or detachment, new blood vessel formation in the eye or an underlying disease. Underlying diseases that may cause vitreous hemorrhage include diabetes, hypertension, carotid artery disease and sickle cell anemia. Of these diseases, diabetes is associated with the highest risk since new blood vessel formation in the eye is stimulated by diabetes. The reason new blood vessels cause bleeding is because of their fragile nature. Older patients, over the age of 50, have higher incidence of vitreous hemorrhage although it can occur at any age. In younger patients, the most common cause of vitreous hemorrhage is trauma, including shaken baby syndrome  .
Symptoms of vitreous hemorrhage include blurry vision that occurs suddenly, light flashes, floaters (spots floating across your vision) and in severe cases blindness. Treatment for vitreous hemorrhage may be simple observation if the physician believes the condition will resolve on its own (which may take months). In severe cases patients may require surgery to remove blood from the eye through a process known as a vitrectomy. Recovery from vitrectomy usually takes around 6 weeks. Investigational research is being done into drugs that help dissolve the abnormalities within the vitreous but these drugs are pending approval from the food and drug administration (FDA).