Vitreous haemorrhage is where there is bleeding into the vitreous. These haemorrhages usually occur suddenly and patients can experience anything from a few floaters to complete visual loss.
Most, however, see many black dots or blobs that may join up to form a ‘cloud’ or ‘cobweb’ in their vision.
This is an urgent situation and patients should ideally be seen within 24 hours, even if a cause of floaters has been previously found.
Once an urgent cause for the haemorrhage has been excluded by an ophthalmologist, the eye may be allowed to clear the blood from the vitreous by itself. This can happen over the course of days, weeks, months or not at all.
How is a vitreous haemorrhage treated?
Most vitreous haemorrhages may be monitored as they clear by themselves. If vitrectomy surgery is recommended it will be following a discussion with the patient and take into account many of the factors mentioned above.
The most urgent reason for surgery is in the case of retinal tear or detachment, when it may even need to be done on the same or next day.
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There are five common causes of spontaneous vitreous haemorrhage:
Retinal Vein Occlusion
The ischaemia that occurs in some branch retinal vein occlusions can lead to the formation of new vessels similar to NVE in proliferative diabetic retinopathy. The bleeding occurs in the same way and a vitrectomy may be done for similar reasons.
Retinal Tear Or Detachment
When a retinal tear occurs there may be a vitreous haemorrhage due to blood vessels within the retina being torn. It is relatively uncommon for the blood to be severe, unless the patient is taking medications that ‘thin’ the blood, such as warfarin, aspirin or clopidogrel. Retinal tears generally can be treated by laser or cryo retinopexy, but may require a vitrectomy if the view of the retina is too poor because of the vitreous haemorrhage. Whilst it is often possible to pick up a retinal tear on B-scan ultrasound, it is not possible to be sure that there isn’t a tear if one isn’t found on the scan.
This is a ballooned out patch of a retinal artery that most commonly occurs in patients with high blood pressure. Sometimes the wall remains intact and the macroaneurysm just leaks and can cause macular oedema. Others can simply burst and the bleeding can often extend into the vitreous. It is very difficult to pick macroaneurysms up on B-scan ultrasound.
Proliferative Diabetic Retinopathy
When an eye moves, the vitreous swirls around within it and can tug on new vessels at the disc (NVD) or new vessels elsewhere (NVE) related to proliferative diabetic retinopathy. Most of the time this does not result in a vitreous haemorrhage, but occasionally one of these new vessels is torn and bleeds. Just like any small blood vessel in the body, this bleeding continues for a short while (or longer if the patient is taking drugs to ‘thin’ the blood) and then stops. If the vitreous remains attached to the blood vessels further bleeding can happen repeatedly.
The only way to remove this blood is by vitrectomy surgery but this usually done if:
- The blood has not cleared after a reasonable length of time
- There are repeated haemorrhages in the same eye
- A B-scan ultrasound shows that there is a threat to long-term vision from a tractional or other type of retinal detachment
- The vision is very bad in both the eye with the vitreous haemorrhage and the other eye also has very bad vision, leaving the patient effectively blind.
- The patient is pregnant or has another cause of rapid worsening of diabetic retinopathy that cannot be treated properly with blood in the eye
- There is a reason to suspect that the vitreous haemorrhage was due to one of the other causes, in which early surgery may prevent permanent visual problems