A retinal haemorrhage is bleeding that occurs within the retina, the light-sensitive tissue lining the back of the eye. This layer contains photoreceptor cells, known as rods and cones, which convert light into neural signals for the brain to process into images. When blood vessels in the retina are damaged, they can leak, causing a haemorrhage that interferes with vision depending on its location and size.
Associated Symptoms
The visual disturbances caused by a retinal haemorrhage can vary widely. Many people report the sudden appearance of floaters, which can look like small specks or fine lines drifting through their field of vision. Vision may also become generally blurred or hazy, and in some cases, straight lines might appear distorted. A shadow or a persistent dark spot can also develop in the visual field.
The severity of these symptoms corresponds to the extent of the bleeding. A significant haemorrhage can lead to a noticeable decrease in visual acuity or vision loss. A very small bleed, however, might not produce any discernible symptoms at all and may be discovered during a routine eye exam.
Underlying Medical Causes
Systemic diseases that affect the body’s vascular system are a common cause of retinal haemorrhages. For example, diabetic retinopathy can cause the growth of fragile, abnormal blood vessels on the retina that are prone to leaking. Similarly, long-term high blood pressure, or hypertensive retinopathy, can damage and weaken retinal arteries, making them susceptible to bleeding. Blood disorders such as leukemia or severe anemia can also interfere with blood cell function and clotting, leading to haemorrhages.
Conditions that originate within the eye are also frequent causes. Retinal vein occlusion, a blockage of a vein that drains blood from the retina, creates a backup of pressure that can force blood out of vessel walls. In the “wet” form of age-related macular degeneration (AMD), abnormal blood vessels grow under the retina and can leak fluid and blood. A posterior vitreous detachment (PVD), where the eye’s gel-like vitreous pulls away from the retina, can sometimes tear a small blood vessel.
External factors can also precipitate bleeding. Direct trauma to the eye or a significant head injury can rupture retinal vessels. Another cause is Valsalva retinopathy, which results from a sudden spike in internal pressure from activities like forceful coughing or heavy lifting. In infants, retinal haemorrhages are strongly associated with abusive head trauma, often called shaken baby syndrome.
The Diagnostic Process
Diagnosing a retinal haemorrhage begins with a comprehensive eye examination. An ophthalmologist will perform a dilated eye exam, using drops to widen the pupil for a clear view of the retina. Using an instrument called an ophthalmoscope, the doctor can visualize the retina to identify the location and size of any bleeding, which helps determine its severity and origin.
To gain a more detailed understanding, advanced imaging tests are often used. Optical Coherence Tomography (OCT) is a non-invasive test that uses light waves to create high-resolution, cross-sectional images of the retina. This allows the doctor to see which layers are affected by the blood and detect any associated swelling.
Another diagnostic tool is fluorescein angiography. This procedure involves injecting a fluorescent dye into an arm vein, which circulates to the retinal blood vessels. As the dye passes through the eye, a special camera takes photographs that highlight blood flow, revealing any leaking, blockages, or abnormal vessels to pinpoint the source of the bleeding.
Medical Interventions
The treatment for a retinal haemorrhage is determined by its underlying cause and severity. For minor bleeding that does not affect central vision, observation is often sufficient. The body can reabsorb the blood over weeks or months, resolving symptoms without intervention.
A primary part of treatment is addressing the root medical condition. Managing systemic diseases like diabetes or high blood pressure is necessary to prevent future bleeding events and protect overall eye health.
More significant haemorrhages may require direct eye treatments. Laser surgery, or photocoagulation, can seal leaking blood vessels to stop them from bleeding further. Another option is intravitreal injections of medications like anti-VEGF drugs to inhibit abnormal vessel growth. In severe cases, a vitrectomy may be performed to surgically remove blood from the eye’s interior and restore vision.