Retinal hemorrhage is bleeding within the retina, the light-sensitive tissue at the back of the eye responsible for transmitting visual information to the brain. When retinal blood vessels rupture or leak, vision can be significantly impaired. This is a serious medical condition requiring prompt evaluation to determine the cause and prevent permanent visual impairment.
Understanding Retinal Hemorrhage
The retina contains a dense network of tiny blood vessels. A hemorrhage occurs when these vessels are damaged, leading to bleeding within the retinal layers. Depending on its location and size, a bleed can manifest as intraretinal, preretinal, or subretinal hemorrhages.
Blood obstructs light from reaching photoreceptors, interfering with visual signal processing. Symptoms include blurred vision, new floaters, or dark spots. Severe cases can cause sudden, significant vision loss.
Major Ocular and Systemic Causes in Adults
Retinal hemorrhages in adults frequently stem from underlying ocular conditions or systemic diseases affecting the body’s vascular network.
Diabetic retinopathy is a prevalent cause, a complication of diabetes where high blood sugar damages retinal blood vessels. This damage can lead to vessel weakening and leakage, causing dot-and-blot or flame-shaped hemorrhages. In advanced proliferative diabetic retinopathy, new, fragile blood vessels can grow on the retina, prone to bleeding into the vitreous.
Hypertensive retinopathy, caused by uncontrolled high blood pressure, contributes to retinal bleeding. Sustained high pressure damages retinal blood vessel walls, increasing permeability and leading to blood and fluid leakage. This often manifests as flame-shaped or dot-blot hemorrhages.
Retinal vein occlusion (RVO) is another common cause, occurring when a retinal vein becomes blocked, often by a blood clot. This blockage prevents blood from draining properly from the retina, causing it to back up and leak into the surrounding tissue. Depending on whether the central retinal vein or a branch vein is affected, the extent of hemorrhage and vision loss can vary.
Wet age-related macular degeneration (AMD) involves the growth of abnormal, fragile blood vessels beneath the macula, the central part of the retina responsible for sharp vision. These new vessels, known as choroidal neovascular membranes, are prone to leaking fluid and blood, resulting in subretinal hemorrhage that can severely distort or reduce central vision.
Direct ocular trauma, such as a blow to the eye, can cause retinal hemorrhages by damaging blood vessels or inducing shearing forces. Pregnancy-related conditions like preeclampsia and eclampsia can also lead to retinal hemorrhages. These involve severe hypertension, causing vascular changes and leakage in the retina, sometimes resulting in serous retinal detachments and hemorrhages.
Causes in Infants and Young Children
Retinal hemorrhages in infants and young children warrant careful consideration due to their distinct and often serious causes.
Abusive Head Trauma (AHT), often referred to as Shaken Baby Syndrome, stands as a primary cause. This results from violent shaking, which can generate extreme acceleration-deceleration forces on the brain and eyes. Such forces can lead to severe, widespread, and multilayered retinal hemorrhages, sometimes accompanied by retinal folds or schisis. These ocular findings are a significant indicator of AHT and are rarely seen in accidental injuries.
Birth trauma can also cause retinal hemorrhages in newborns, particularly following difficult or prolonged deliveries. The compression of the infant’s head during passage through the birth canal can lead to an acute increase in intracranial pressure, affecting retinal venous flow. These hemorrhages are generally less severe, often intraretinal, and typically resolve spontaneously within weeks, distinguishing them from those caused by abuse.
Retinopathy of Prematurity (ROP) is another cause, affecting premature infants whose retinal blood vessels have not fully developed. When normal vessel growth is disrupted, abnormal, fragile vessels can proliferate, leading to leakage and bleeding within the retina. In severe cases, this can result in vitreous hemorrhage and even retinal detachment.
Certain systemic blood disorders like leukemia and severe anemia can manifest with retinal hemorrhages in children. In leukemia, the abnormal proliferation of white blood cells can affect blood vessel integrity, leading to bleeding. Severe anemia, characterized by very low hemoglobin levels, can also cause retinal hemorrhages due to compromised blood vessel function and increased fragility.
Other Contributing Factors and Less Frequent Causes
Beyond the more common conditions, several other factors and less frequent causes can lead to retinal hemorrhages.
Bleeding disorders, such as hemophilia or thrombocytopenia, impair the blood’s ability to clot effectively. This systemic clotting dysfunction increases an individual’s susceptibility to bleeding throughout the body, including within the delicate vessels of the retina.
Medications like anticoagulants and antiplatelets, commonly referred to as blood thinners, are prescribed to prevent blood clots but inherently increase the risk of bleeding. While beneficial for cardiovascular health, these drugs can make retinal vessels more prone to hemorrhage, particularly in individuals with pre-existing conditions like hypertension.
Terson’s Syndrome is a specific condition where a sudden increase in intracranial pressure, often resulting from a subarachnoid hemorrhage or traumatic brain injury, leads to retinal hemorrhage. The elevated pressure is thought to be transmitted to the optic nerve sheath, compressing the central retinal vein and causing retinal vessels to rupture.
Valsalva retinopathy occurs due to a sudden, transient increase in intrathoracic or intra-abdominal pressure. Activities like severe coughing, vomiting, straining during bowel movements, or heavy lifting can cause a rapid rise in venous pressure within the eye, leading to the rupture of superficial retinal capillaries and resulting in a preretinal hemorrhage.
Sickle cell retinopathy is a complication of sickle cell disease where abnormally shaped red blood cells can block retinal blood vessels. This blockage leads to areas of reduced blood flow and oxygen deprivation, prompting the growth of new, fragile blood vessels that are prone to leakage and bleeding.
High altitude retinopathy can develop in individuals exposed to low oxygen levels. The hypoxic environment can lead to changes in retinal blood vessels, including dilation and increased permeability, resulting in hemorrhages. These are often transient and resolve upon descent.