Safe Diagnosis and Management
What is Vitreous Haemmorhage?
Vitreous haemmorhage is the term used to describe bleeding inside the eye, which blocks light from being transmitted to the retina. This results in shadows blocking vision and in severe cases complete loss of vision.
In order to understand the effect vitreous haemorrhage has on vision it is helpful to understand how the eye works. The eye can be compared to a camera. The pupil of the eye is like the aperture of a camera, regulating the amount of light entering the eye. Light passes through the cornea, pupil, lens and vitreous and is focussed on the retina.
The retina is the light-sensitive nerve tissue that lines the inner wall of the eye, like the film in a camera. Rays of light enter the eye, passing through the cornea, pupil and lens before focusing on to the retina. The retina contains photoreceptors which convert light into electrical impulses. In the healthy eye these impulses are sent via the optic nerve to the brain, where sight is interpreted as clear, bright images.
What are the symptoms of Vitreous Haemmorhage?
Patients may report seeing clumps of black floating spots, a shower of red or brown spots, clouds obscuring the vision, or in severe cases complete loss of vision.
What are the causes of Vitreous Haemmorhage?
Normally the vitreous jelly inside the eye is clear and contains no blood vessels. Bleeding into the vitreous usually occurs due to bleeding from abnormal blood vessels on or below the retinal surface, or from trauma to the retina. Many different eye conditions can cause a vitreous haemorrhage. The most common causes include:
Retinal tear: as the vitreous contracts during posterior vitreous detachment (“PVD”) it may pull a hole or tear in the retina. Sometimes as this occurs one of the retinal blood vessels may be torn, causing bleeding into the vitreous cavity. If the patient is not diabetic, there is a 2 in 3 chance that there is a retinal tear hidden behind the bleeding.
Diabetic retinopathy: in severe cases of diabetic retinopathy abnormal new blood vessels grow on the surface of the retina and may bleed into the vitreous.
Retinal vein occlusion: Blockage of one of the retinal veins can result in abnormal new blood vessels growing on the surface of the retina, much as in severe diabetic retinopathy. These vessels may bleed into the vitreous. Retinal laser treatment may be recommended to reduce this risk after a retinal vein occlusion.
Macular degeneration: Rarely, bleeding may occur as a complication of wet macular degeneration.
Careful examination of the affected eye and the fellow eye, as well as a directed history and appropriate tests can usually identify the cause of haemmorhage.
What is the treatment for Vitreous Haemmorhage?
Mild cases of vitreous haemmorhage can be closely observed to clear spontaneously. This is particularly so in cases where the cause is clear, such as diabetic eye disease or retinal vein occlusion. This may take a few weeks, and sometimes the underlying disease pathology can be treated with an intravitreal injection.
If a haemmorhage occludes vision, or prevents examination of the underlying retina microincision vitrectomy surgery can remove the blood and identify and treat the underlying pathology.