Retinal hemorrhage is bleeding within or around the retina, the light-sensitive tissue lining the back of the eye. It can range from a few tiny dots visible only through a dilated exam to large pools of blood that block central vision almost completely. The causes span a surprisingly wide spectrum, from everyday conditions like diabetes and high blood pressure to rare events like sudden surges in brain pressure or climbing to extreme altitudes. Because the retina is the one place in the body where blood vessels can be observed directly and non-invasively, retinal hemorrhages often serve as a window into what is happening in the rest of the body, sometimes revealing systemic disease before any other symptom appears.
How Bleeding Happens in the Retina
The retina is fed by a delicate network of tiny blood vessels. These vessels are lined by endothelial cells and supported by specialized cells called pericytes, which wrap around the outside of capillaries and help regulate blood flow and vessel stability. When pericytes are lost or damaged, as happens in diabetes, the vessels become fragile, leaky, and prone to ballooning into microaneurysms that can rupture. Disruption of the signaling between endothelial cells and pericytes leads to vessel enlargement, increased permeability, and hemorrhage.
The shape and location of the bleed often tell a clinician what caused it. Flame-shaped hemorrhages spread along the nerve fiber layer near the retinal surface and are classic in high blood pressure. Dot and blot hemorrhages sit in the deeper retinal layers and are hallmarks of diabetic eye disease. Subretinal hemorrhages pool beneath the retina itself and are common in age-related macular degeneration. Pre-retinal hemorrhages collect between the retina and the vitreous gel that fills the eye, sometimes settling into a boat-shaped layer visible during examination.
Diabetes and Diabetic Retinopathy
Diabetes is one of the most common causes of retinal hemorrhage worldwide. Chronic high blood sugar damages the retinal capillaries over years, leading to progressive changes collectively called diabetic retinopathy. Retinal ischemia and hemorrhage are hallmarks of the disease as it worsens, and they can eventually trigger the growth of abnormal new blood vessels, swelling of the macula, and severe vision loss.1PubMed Central. Thrombosis and Hemorrhage in Diabetic Retinopathy: A Perspective from an Inflammatory Standpoint The process is not just about sugar damaging vessel walls. Inflammatory mediators and clotting-system proteins like plasma kallikrein and thrombin accumulate in the diabetic retina, worsening capillary dysfunction and promoting further bleeding.
At the cellular level, loss of pericytes from capillary walls is considered the key early event. When pericytes disappear, endothelial cells proliferate abnormally and form microaneurysms rather than healthy vessel branches. These microaneurysms are the earliest visible sign on a retinal exam and the source of the dot and blot hemorrhages that define non-proliferative diabetic retinopathy.2Diabetes & Metabolism Journal. Pathophysiology of Diabetic Retinopathy: The Old and the New In later stages, widespread capillary closure starves the retina of oxygen, and the eye responds by growing fragile new vessels that bleed easily into the vitreous cavity, sometimes causing sudden, dramatic vision loss.
High Blood Pressure
Persistently elevated blood pressure damages retinal arterioles through a different pathway. The walls of small arteries thicken and narrow, and in severe or “malignant” hypertension the smooth muscle in the vessel wall can die outright, allowing blood to leak into the surrounding nerve fiber layer as flame-shaped hemorrhages.3PubMed Central. Ophthalmoscopic findings in malignant hypertension Cotton-wool spots, which look like fluffy white patches on the retina, often appear alongside these hemorrhages; despite their name, they are not deposits but tiny areas of retinal infarction where nerve fibers have been cut off from blood supply.
Clinicians grade hypertensive retinopathy on a scale from mild, where changes are limited to narrowed arterioles and subtle wall changes, through moderate, where hemorrhages and cotton-wool spots appear, to severe, where the optic disc itself swells.4Academic Press. Hypertensive retinopathy Finding retinal hemorrhages on a routine eye exam can be the first clue that someone’s blood pressure has been dangerously high, which is one reason comprehensive dilated exams matter even when vision seems fine.
Retinal Vein Occlusion
A retinal vein occlusion occurs when a clot or compression blocks one of the veins draining blood from the retina. The backed-up blood leaks from distended capillaries, producing a dramatic pattern of hemorrhages, swollen veins, and cotton-wool spots along the affected drainage area. Branch retinal vein occlusion, the more common form, typically happens where a hardened artery crosses over and compresses a vein. It tends to affect people in their sixties and seventies and is strongly associated with the same risk factors behind heart disease and stroke: hypertension, diabetes, and high cholesterol.5Patient Care. Branch Retinal Vein Occlusion Central retinal vein occlusion, where the main vein leaving the eye is blocked, produces more widespread hemorrhages and carries a higher risk of complications like abnormal new vessel growth.
Carotid Artery Disease and Ocular Ischemic Syndrome
When the carotid arteries in the neck become severely narrowed, the eye on that side can be starved of blood flow, a condition called ocular ischemic syndrome. The retinal findings are distinctive: mid-peripheral hemorrhages appeared in roughly four out of five affected eyes in one early case series, often alongside dilated veins and new vessel growth.6PubMed. The ocular ischemic syndrome. Clinical, fluorescein angiographic and carotid angiographic features. Some hemorrhages in this syndrome have a white center, an unusual appearance that can help distinguish the condition from other causes of retinal bleeding.7PubMed. White-centered retinal hemorrhage in ocular ischemic syndrome resolved after carotid artery stenting Because the underlying problem is vascular obstruction in the neck rather than in the eye itself, treatment often involves vascular surgery or stenting to restore blood flow to the brain and eye.
Birth-Related Retinal Hemorrhage
Retinal hemorrhages in newborns are far more common than most parents realize. Roughly a quarter to a third of healthy babies born vaginally have some degree of retinal bleeding, and the rate climbs with instrumented deliveries. A systematic review found hemorrhages in about a quarter of spontaneous vaginal deliveries, rising to roughly 43% after vacuum extraction and 52% after combined forceps-and-vacuum deliveries.8PubMed. Newborn retinal hemorrhages: a systematic review A large prospective study of over 2,000 births put the overall rate at about 32%, with vacuum-assisted delivery as the strongest independent risk factor. Two-thirds of the hemorrhages in that study disappeared within the first week, and all had resolved within four weeks.9PubMed. Birth-related retinal hemorrhages in the newborn: incidence and relationship with maternal, obstetric and neonatal factors
Cesarean delivery is associated with a lower rate. One study of nearly 1,200 infants found that vaginal delivery was roughly four times more likely to produce retinal hemorrhages compared with cesarean delivery, likely because the compressive forces on the baby’s head during passage through the birth canal briefly raise venous pressure in the eye.10PubMed. Birth-related retinal hemorrhages in healthy full-term newborns and their relationship to maternal, obstetric, and neonatal risk factors The bleeds are typically bilateral and concentrated near the back of the eye, and they almost never have lasting effects on the baby’s vision. The vast majority clear on their own within days to weeks, though isolated cases can persist up to about six weeks.11PubMed. Newborn retinal hemorrhages: a systematic review
The Forensic Controversy in Infants
Retinal hemorrhages have long been considered one of the hallmarks of abusive head trauma in infants, and they remain an important part of the clinical evaluation when abuse is suspected. However, the assumption that certain patterns of retinal hemorrhage can reliably distinguish abusive from non-abusive injury has been challenged. A 2023 review in a leading pediatric neurology journal concluded that retinal hemorrhage patterns alone cannot distinguish abuse from other causes.12PubMed. Retinodural haemorrhage of infancy, abusive head trauma, shaken baby syndrome: The continuing quest for evidence This does not mean the finding is irrelevant in child protection cases, but it does mean that retinal hemorrhage by itself should not be treated as proof of abuse. Clinical context, other injuries, and the full medical history all matter. The ongoing debate has real consequences in both directions: an innocent caregiver can face prosecution based on a misinterpreted finding, and an abused child can be missed if clinicians rely too heavily on any single sign.
High Altitude
Climbers and trekkers ascending above roughly 4,000 to 5,000 meters sometimes develop retinal hemorrhages even with no pre-existing eye disease. The low oxygen environment at extreme altitude increases vascular permeability and causes metabolic byproducts to accumulate, leading to retinal edema and hemorrhage.13PubMed Central. High-altitude retinopathy and retinal hemorrhage: A case report Interestingly, hemorrhages sometimes appear not at the highest point of the climb but after descent to a lower camp, suggesting that a reperfusion-type injury may play a role. As oxygen levels rise again, free radicals generated during reperfusion can damage already-stressed vessel walls and trigger visible bleeding.14PLoS ONE. Delayed Appearance of High Altitude Retinal Hemorrhages Most high-altitude retinal hemorrhages are asymptomatic and resolve on their own within weeks of returning to lower elevation, but hemorrhages that land on the macula can temporarily impair central vision.
Valsalva Retinopathy and Sudden Pressure Spikes
A Valsalva maneuver is any forceful exhalation against a closed airway: heavy lifting, straining during a bowel movement, violent coughing or vomiting, even vigorous blowing of a musical instrument. The spike in pressure inside the chest and abdomen transmits backward into the veins of the head and eye, and in susceptible people it can rupture the small capillaries near the center of the retina.15PubMed Central. Valsalva Retinopathy in a Young Patient: A Case Report The resulting bleed, called Valsalva retinopathy, typically presents as a round pocket of dark blood trapped between the retina and the vitreous right over the macula. It can cause sudden, painless loss of central vision. The good news is that most cases resolve spontaneously as the blood reabsorbs over weeks to months. In more severe or slow-to-clear cases, a laser can be used to puncture the membrane trapping the blood, letting it disperse into the vitreous where it clears faster.
Brain Hemorrhage and Terson Syndrome
A sudden rise in pressure inside the skull, most classically from a ruptured brain aneurysm causing subarachnoid hemorrhage, can produce bleeding inside the eye, a phenomenon known as Terson syndrome. The eye bleeds because the optic nerve sheath connects the intracranial space to the area behind the eye; when pressure spikes, it compresses the retinal veins and forces blood out of fragile vessels. One study found retinal or vitreous hemorrhage in roughly 18% to 20% of patients with spontaneous subarachnoid hemorrhage.16PubMed Central. Terson Syndrome in Aneurysmal Subarachnoid Hemorrhage: A Case Report The finding is not exclusive to aneurysm rupture; a study of patients with severe traumatic brain injury found retinal or vitreous hemorrhage at a similar rate, suggesting the trigger is acutely raised intracranial pressure regardless of its cause.17Journal of Neurosurgery. Terson’s syndrome in subarachnoid hemorrhage and severe brain injury accompanied by acutely raised intracranial pressure The presence of Terson syndrome in a patient with a brain bleed is associated with worse neurological outcomes, so identifying it carries prognostic value.
Blood Disorders and Leukemia
Retinal hemorrhages can also be driven by problems with the blood itself. Severe anemia, low platelet counts, and blood cancers like leukemia all weaken the ability of blood to clot normally or compromise the integrity of vessel walls through abnormal cell infiltration. In acute leukemia, patients who develop retinal hemorrhage tend to have lower hematocrit levels than those who do not, reflecting the degree to which the disease has disrupted normal blood-cell production.18PubMed Central. Secondary Ocular Manifestations in Acute Leukemia: Clinical Patterns and Hematologic Correlates In these cases, the retinal hemorrhage is a marker of systemic severity, and treatment focuses on managing the underlying blood disorder rather than the eye itself.
Anticoagulant Medications and Risk
People taking blood-thinning medications sometimes worry about eye bleeds, and the concern has some basis. An analysis of adverse-event reporting data found that newer oral anticoagulants were associated with retinal and vitreous hemorrhage at rates above what would be expected by chance. Rivaroxaban showed the strongest signal, while dabigatran also showed a meaningful association.19PubMed Central. Risk of intraocular hemorrhage with new oral anticoagulants That said, the absolute risk remains small for most patients, and it is important not to overreact to pharmacovigilance signals, which detect associations but cannot prove causation. A separate analysis from a large clinical trial of patients with age-related macular degeneration found that antiplatelet or anticoagulant use was not significantly associated with hemorrhage overall, though it was associated with hemorrhage in participants who also had hypertension.20PubMed Central. Association between Antiplatelet or Anticoagulant Drugs and Retinal or Subretinal Hemorrhage in the Comparison of Age-Related Macular Degeneration Treatments Trials For anyone already on anticoagulants who has a condition predisposing them to retinal hemorrhage, the interplay of bleeding risk and clotting risk is worth discussing with their care team rather than making unilateral changes to medication.
How Retinal Hemorrhage Is Detected
The classic method is direct or indirect ophthalmoscopy during a dilated eye exam, where a clinician uses bright light and magnifying lenses to inspect the retina. Many hemorrhages are discovered incidentally during routine exams in people who have no symptoms. When hemorrhage is suspected or confirmed, optical coherence tomography (OCT) provides a cross-sectional view that can pinpoint exactly which retinal layer the blood occupies. In one imaging study of a specific type of central hemorrhage, OCT revealed well-defined, round hyperreflective lesions tracking along the fibers of the Henle layer beneath the fovea, a level of detail impossible to achieve with surface examination alone.21RETINA. CENTRAL BOUQUET HEMORRHAGE: Clinical and Multimodal Imaging Features Fluorescein angiography, in which a dye is injected into the bloodstream and photographed as it passes through retinal vessels, helps identify the source of bleeding and any associated areas of leakage or vessel closure.
Artificial intelligence is increasingly being tested for automated detection of retinal hemorrhages from standard fundus photographs. One deep-learning framework achieved sensitivity and specificity both above 98% when identifying hemorrhages from retinal images, outperforming several earlier automated methods.22Elsevier / Biomedical Signal Processing and Control. Deep learning enabled hemorrhage detection in retina with DPFE and splat segmentation in fundus images If screening tools like this prove reliable in real-world clinics, they could help flag patients who need specialist referral faster, particularly in settings without easy access to an ophthalmologist.
Treatment Options
Treatment depends entirely on the cause and severity. Many retinal hemorrhages, especially small ones from well-controlled hypertension or a Valsalva episode, simply reabsorb on their own without intervention. For hemorrhages associated with abnormal blood-vessel growth, as in diabetic retinopathy or wet age-related macular degeneration, anti-VEGF injections are the first-line treatment. These drugs block the signaling molecule that drives leaky new vessel formation. In one study of patients with macular hemorrhage, an average of four anti-VEGF injections brought vision from roughly 20/710 to about 20/100.23PubMed. Anti-VEGF response in macular hemorrhage and incidence of retinal pigment epithelial tears In traumatic submacular hemorrhage, anti-VEGF injections likewise produced significant reductions in the thickness of blood under the fovea and meaningful gains in visual acuity.24PubMed. Efficacy of anti-VEGF intravitreal injection in traumatic submacular hemorrhage: a retrospective study
Laser treatment has a narrower role. Subthreshold laser applied directly to a bleeding retinal arterial macroaneurysm can promote clotting and shrinkage of the abnormal vessel.25Asia-Pacific Journal of Ophthalmology. Laser and Anti-Vascular Endothelial Growth Factor Agent Treatments for Retinal Arterial Macroaneurysm However, wavelength choice matters: experimental work has shown that yellow and orange laser wavelengths are absorbed directly by red blood cells and can destroy the inner layers of the retina, while a 630-nanometer red laser passes through blood to reach the target tissue underneath more safely.26PubMed. Dye laser photocoagulation through experimentally induced retinal hemorrhage
When a large hemorrhage sits beneath the macula and threatens permanent damage, surgical removal via vitrectomy may be necessary. In some procedures, a clot-dissolving agent like tissue plasminogen activator is injected under the retina to liquefy the blood before it is aspirated through a tiny opening.27Ophthalmology. Vitrectomy for macular hemorrhage associated with retinal arterial macroaneurysm Surgery carries its own risks, so it is generally reserved for eyes where the hemorrhage is thick, central, and unlikely to clear on its own in a time frame that would preserve the photoreceptors underneath.
What Determines Visual Outcome
Not all retinal hemorrhages affect vision the same way. Location is the single most important variable: a hemorrhage in the far periphery of the retina may go completely unnoticed, while even a thin layer of blood under the fovea can blur central vision substantially. Among subretinal hemorrhages specifically, thickness matters more than diameter. A study of prognostic factors found that patients with thick hemorrhages causing obvious elevation of the fovea had significantly worse final visual acuity than those with thin hemorrhages, while the overall width of the hemorrhage was not a significant predictor.28PubMed. Factors prognostic of visual outcome in patients with subretinal hemorrhage The reason is that a thick clot sitting against the photoreceptors is toxic to them: iron released from degrading red blood cells and the physical barrier blocking nutrients both contribute to photoreceptor death if the blood lingers.
Speed of treatment matters, too. In neovascular age-related macular degeneration with submacular hemorrhage, a clinical trial of intravitreal aflibercept showed that more than half of treated patients gained 15 or more letters of vision (roughly three lines on an eye chart) over about a year, and none experienced a loss of that magnitude.29SpringerLink. Intravitreal aflibercept for submacular hemorrhage secondary to neovascular age-related macular degeneration and polypoidal choroidal vasculopathy The takeaway is that submacular hemorrhage is no longer the visual death sentence it once was, provided treatment begins promptly.
When to Seek Urgent Care
Many retinal hemorrhages produce no symptoms at all and are found during routine exams. But certain warning signs should prompt an urgent visit to an eye care professional: a sudden shower of new floaters, a dark curtain or shadow creeping across part of the visual field, or an abrupt painless drop in central vision. These can signal a hemorrhage into the vitreous cavity or a large bleed under the macula, both of which benefit from rapid evaluation and, in many cases, treatment within days rather than weeks. People with diabetes, uncontrolled hypertension, blood-clotting disorders, or those on anticoagulant therapy are at heightened baseline risk and should not attribute new visual symptoms to aging without getting checked. For everyone else, a comprehensive dilated eye exam at the intervals recommended by their eye doctor remains the most reliable way to catch asymptomatic retinal hemorrhage before it threatens vision.