Retinal vein occlusion
Retinal vein occlusion (RVO) is the blockage of a vein carrying de-oxygenated blood from the retina of the eye (back towards the heart for oxygenation). This blockage results in reduced vision.
The reduction in vision can be severe and occurs because blockage of the vein causes some blood to leak out of the vein itself, into the surrounding tissues. Clear fluid also leaks out into the tissues of the retina, effectively ‘water-logging’ it so that the image formed on the retina is not transmitted clearly to the brain, hence the images normally called "sight" are not received /perceived normally.
Note that a retinal vein occlusion is a type of retinal vascular occlusion, the other type of retinal vascular occlusion being a retinal artery occlusion.
Retinal vein occlusions are a moderately common type of retinal vascular disorder.
They can occur at almost any age (but most often in middle-age and beyond). There is a huge range in severity from barely perceptible to painful with loss of sight in affected eye.
There are several types of retinal vein occlusions including:
Types of retinal vein occlusions:
- Central retinal vein occlusion (CRVO)
- non-ischaemic - milder form, approx. 75% of CRVOs. May resolve fully with good visual outcome - or progress to the ischaemic type.
- ischaemic - severe form, may result in neovascular glaucoma and a painful blind eye.
- Branch retinal vein occlusion (BRVO)
- 3x more common than CRVOs.
- Several subclassifications of BRVO, according to whether a major branch, a minor macular branch or a peripheral branch is affected.
- Hemiretinal vein occlusion
- May be inferior (lower-half of the visual field in the affected eye) or superior (upper-half of the visual field in the affected eye)
Retinal vein occlusions are a large and complicated subject - with symptoms, management and treatment,
possible complications, and outcomes varying according to the type of retinal vein occlusion and also varying considerably
from case to case - note the range in severity mentioned above.
This brief entry is included for completeness to mention a wide range of ophthalmic conditions in this section - for more information ask an expert or consult a more specialized source.
More about Ophthalmology:
This section includes short definitions
of many diseases, disorders, and conditions of the eyes and visual system.
For definitions of other terms in this category, choose from the list
to the left (but note that this is not a complete/exhaustive list).
Other related pages include
- A diagram of the eye
- Definitions and descriptions of the parts of the eye
- A concise description of the human retina
- Definitions of parts of the retina
- Clinical and surgical procedures re. eyes and human visual system
For further information see also our pages of books about ophthalmology.
The following books may also be of interest:
