Vitreous Haemorrhage

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:

• Retinal tear: Incidents as described above.
• 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.