A retinal hemorrhage, or bleeding within the light-sensitive tissue at the back of the eye, is a serious medical event that warrants immediate professional evaluation. While not every small bleed requires emergency surgery, any sudden change in vision caused by retinal bleeding must be treated as an ocular emergency to preserve sight. The retina converts light into neural signals, and disruption from blood blocking light can lead to permanent vision damage. Prompt assessment is necessary to determine the severity and the underlying cause of the bleeding.
Defining Retinal Hemorrhage
A retinal hemorrhage involves the leakage of blood from damaged blood vessels into or around the retina. The location of the bleed determines its appearance and immediate impact on vision. Superficial hemorrhages in the nerve fiber layer appear as elongated, streak-like “flame-shaped” spots.
Deeper bleeds, often called “dot-and-blot” hemorrhages, collect in small, circular areas and are associated with systemic conditions. More severe types include preretinal or subhyaloid hemorrhages, which pool blood between the retina and the vitreous gel. When blood leaks entirely into the vitreous body, it is classified as a vitreous hemorrhage and typically causes the most significant vision loss.
Recognizing the Warning Signs
The most telling sign of a retinal hemorrhage is the sudden onset of visual disturbances. Patients frequently report seeing a “shower” of floaters—numerous dark spots or thread-like shapes that drift across their field of view. This rapid increase signals that blood cells have entered the vitreous humor and are casting shadows on the retina.
A hemorrhage can also manifest as blurred or hazy vision, especially when the bleeding is diffuse or located near the macula, the center for sharp sight. In extensive cases, a patient may perceive a distinct shadow, a dark curtain, or partial vision loss. A reddish or brownish tinge to the vision is sometimes reported if a larger volume of blood has leaked into the vitreous space. The experience of flashing lights, known as photopsia, can accompany the visual symptoms, suggesting that the bleeding may be associated with traction or a tear in the retinal tissue. Any sudden and unexplained decline in visual acuity requires urgent evaluation.
Primary Causes and Risk Factors
Retinal hemorrhages often manifest from underlying systemic diseases that compromise the vascular network. One of the most common causes is diabetic retinopathy, where high blood sugar damages retinal blood vessels, leading to leakage and the growth of fragile new vessels prone to bleeding. In its advanced, or proliferative, stage, diabetic retinopathy often triggers severe preretinal or vitreous hemorrhages.
Uncontrolled hypertension is another risk factor because the force of blood flow can weaken and rupture retinal arterioles, leading to flame-shaped hemorrhages. A sudden, severe spike in blood pressure can cause widespread bleeding known as hypertensive retinopathy. Vascular occlusions, such as a Retinal Vein Occlusion (RVO), occur when a retinal vein becomes blocked, causing blood backup that ruptures vessel walls.
Local events can also cause bleeding, most notably direct blunt force trauma to the eye or head, which can tear retinal vessels. Additionally, the wet form of Age-related Macular Degeneration (AMD) is characterized by the growth of abnormal, leaky blood vessels beneath the retina, which can bleed into the subretinal space. Certain blood disorders that affect clotting, or a sudden increase in thoracic pressure from severe coughing or heavy lifting (Valsalva retinopathy), can also trigger a retinal hemorrhage.
Emergency Medical Intervention and Treatment
The initial emergency evaluation involves a comprehensive dilated eye examination to visualize the retina and characterize the hemorrhage’s location and extent. Specialized imaging tests, such as Optical Coherence Tomography (OCT), provide high-resolution cross-sectional images to map the exact layers affected by the blood. Fluorescein angiography may also be performed, injecting a dye to highlight leaking or abnormal blood vessels that are the source of the hemorrhage.
If the hemorrhage is small and does not obscure the macula, observation may be the initial course of action, as the eye can often reabsorb the blood over several weeks or months. For more significant bleeds, treatment is tailored to the underlying cause and location. Laser photocoagulation is commonly used to seal off abnormal, leaking blood vessels, particularly in cases of proliferative diabetic retinopathy.
Intravitreal injections of anti-Vascular Endothelial Growth Factor (anti-VEGF) medications suppress the growth of new, fragile vessels and reduce fluid leakage in conditions like wet AMD or complications of RVO. If the blood accumulation is dense, such as in a non-clearing vitreous hemorrhage, a surgical procedure called a pars plana vitrectomy may be necessary. This involves removing the vitreous gel and the suspended blood to restore a clear path for light to reach the retina.