The vitreous fills most of your eye.
It’s the jelly-like material that allows light to pass from the lens to the retina. Normally this area of our eyes remains clear and unobstructed. In certain circumstances, however, the nearby blood vessels can bleed into those clear tissues (a haemorrhage). This can prevent light from reaching the retina, leading you to experience problems with your vision. Some haemorrhages will simply disappear naturally given time, while others may need further treatment. For this reason it’s important not to ignore the symptoms of a haemorrhage if they occur. With a careful analysis of your eyes and your medical history, we can help you to explore the best options for treatment.
The term vitreous haemorrhage implies bleeding into the vitreous cavity. This is the chamber of the eye, which is filled with clear, jelly-like tissue (known as vitreous gel or fluid). The degree of visual loss from a vitreous haemorrhage depends upon the extent of the bleeding; it can range from mildly troublesome floaters to a complete loss of all useful vision.
The vitreous cavity of a healthy eye is filled with nothing other than clear vitreous gel. Bleeding can result either from normal retinal vessels that have been subjected to some kind of trauma, or from abnormal blood vessels that have developed on the surface of the retina in response to an underlying retinal problem (a pathology).
Normal blood vessels can tear when the vitreous separates from the retina during a posterior vitreous detachment (PVD). This is more common in short-sighted (myopic) eyes and always raises the possibility that the retina may have been torn. This in turn puts the eye at risk of retinal detachment.
While it’s possible for a direct trauma to the eyeball to cause bleeding, the eye is actually remarkably resilient – even a hefty knock may not cause a vitreous haemorrhage.
Bleeding from abnormal retinal vessels can occur in a number of conditions. You may have had one of these diagnosed already, prior to the vitreous haemorrhage, or you may even have started some treatment for them.
The most common causes of vitreous haemorrhage are:
- Diabetic retinopathy: Abnormal blood vessels grow on the surface of the retina in response to poor retinal blood flow. You may already have been diagnosed with this, and even had laser treatment for it.
- Retinal vein occlusion: Blockage of the retinal vein or one of its branches results in poor blood flow to an area of the retina. The retina responds by growing abnormal blood vessels, which unfortunately do little to help retinal function but are fragile and susceptible to bleeding.
- Age-related macular degeneration (AMD): About 10% of patients with macular degeneration develop the “wet” form of the disease. This is where an abnormal meshwork of blood vessels grows beneath the central macular retina. Although very uncommon, patients with severe wet macular degeneration can develop a “breakthrough” bleed into the vitreous cavity of the eye.
Vitreous haemorrhage causes a spectrum of visual symptoms, which vary in severity. These include:
- floaters, which may be anything from small dots to large clouds of “debris”.
- a haziness of the entire visual field.
- profound visual loss, so that you would struggle even to see “hand movements” in front of your eyes.
This depends upon a number of factors, but some important things to consider are:
- If you have a pre-existing, documented abnormality, such as abnormal blood vessels due to diabetic retinopathy. In this situation it may be appropriate to wait a few weeks to see if the bleeding clears spontaneously.
- If you have suffered a severe bleed with profound visual loss, resulting in an obscured view of the retina; in this case we will recommend more urgent surgery.
- Patients with no pre-existing ocular disease. Here we might be concerned that the bleeding has been caused by a posterior vitreous detachment (PVD) and that shrinkage of the vitreous jelly, sufficient to cause bleeding, may also have torn the retina. The peripheral retina is where tears normally occur; if we cannot visualise this clearly then urgent surgery is essential. The risk of retinal detachment accompanying vitreous haemorrhage increases if you are short-sighted, or when your fellow eye has already suffered a retinal detachment.