The retina is a fine sheet of nerve tissue lining the inner surface of the eye that processes the images focused on it by the cornea and the lens. If there is a tear or hole in the retina then the internal fluids of the eye may leak through it, causing separation of the retina from the underlying tissues. When this happens the retina cannot compose a clear picture from the incoming light rays and vision becomes blurred and dim.
Who is at risk?
Retinal detachment usually occurs in middle aged, short sighted people. It is however quite uncommon, affecting only about one person in 10,000. Very rarely, younger people can have a weakness of the retina, or it can detach as a result of a blow to the head. It does not happen as a result of straining your eyes, bending or heavy lifting.
If a person has had a retinal detachment in one eye, they are at increased risk of developing one in the other eye. The chance of this happening is about one in ten.
Can it be prevented?
If there is a family history of retinal detachment, or a doctor finds a weakness in a person’s retina, then preventive laser or freezing treatment may be needed. In most cases, however preventive action is not possible.
What are the symptoms?
The most common symptom of retinal detachment is a shadow spreading across the vision of one eye. Sufferers may also experience bright flashes of light and/or showers of dark spots called floaters. These symptoms are never painful.
Many people experience flashes or floaters and these are not necessarily a cause for alarm. However if they are severe and seem to be getting worse, and/or the person is losing vision then they should see a doctor urgently. Prompt treatment can often minimise eye damage.
What is the treatment?
If help is sought early, it may only be necessary to have a laser or freezing treatment, usually performed under a local anaesthetic.
Often however, an operation is required to repair the hole in the retina. This is usually carried out under general anaesthetic, and in 90% of cases a single operation is sufficient to repair the damage. The eye is not removed from its socket for this operation. The operation does not normally cause much pain but the eye will be sore and swollen for a few days afterwards. A stay in hospital for two or three days is usual during which time the patient will be encouraged to get up and carry on as normal. Sometimes they may be asked to keep their head in a particular position to aid the healing process. Normal activities can be resumed as soon as the person feels able.
The amount of vision after a successful operation depends on how much the retina has detached and for how long. The shadow caused by the detachment will disappear in all cases when the retina has been put back in place. However, if the detachment involves the part of the retina responsible for central vision, this may not recover. The longer this part of the retina has been detached, the smaller the chance that the central vision will recover to its former level. Even if this is the case, there will still be some useful vision left.
What if the retina is not put back in place?
If an operation is not carried out, or if the treatment is unsuccessful, most people will lose all useful vision. Occasionally, if the detachment involves the lower portion of the retina, some vision may recover by itself.
What if sight cannot be fully restored?
If full sight cannot be restored, much can be done to help a person use their remaining vision as fully as possible. Their doctor should be asked to refer them to the hospital low vision clinic. There are a variety of optical aids available, such as brighter reading lights, simple magnifying glasses and more sophisticated equipment that can help.