Glaucoma is the name for a group of eye conditions in which the optic nerve (the nerve at the back of the eye) is damaged, often in association with raised pressure within the eye. This leads to a reduction in the field of vision and in the ability to see clearly. In most cases glaucoma sufferers will experience no symptoms until significant damage has occurred.
Who is at risk from glaucoma?
People aged 40 and over are at greater risk from glaucoma and there is an increasing risk with every decade of life. Those with a family history of glaucoma in close relatives, or in certain ethnic groups are considered to have a greater than average risk. People who diabetic or very short- sighted are also more prone to glaucoma.
How do you check for glaucoma?
There are three main tests that may be carried out by an optometrist to check for glaucoma:
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Ophthalmoscopy - checking the appearance of the optic disc (where the optic nerve joins the eye) using an ophthalmoscope, a special torch for looking into the eyes.
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Visual field assessment - testing the field of vision using small points of light to check for blind spots.
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Tonometry - measuring the pressure within the eye, either using an instrument that emits a small puff of air onto the surface of the eye, or placing a probe against the eye after it has been numbed with anaesthetic drops.
Other instruments are now available for detecting and monitoring glaucoma but these are the most commonly used tests.
What can be done?
If detected early enough, glaucoma can usually be treated. In most cases eye drops to reduce the pressure in the eye will be prescribed, although in some cases an operation is needed.
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Retinal detachment is a rare but serious and sight-threatening event which occurs when the retina – the light-sensitive inner lining of the back of the eye – becomes separated from the underlying tissue. This may be caused by a hole or tear in the retina which allows fluid to get underneath, weakening the attachment of the retina which then becomes detached - rather like wallpaper peeling off a damp wall. Detached retina can also be caused by an injury or may be a consequence of other eye conditions or surgery.
What are the symptoms?
The most common symptom is a shadow or curtain spreading across the vision of one eye. You 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 vision is being lost, a doctor should be seen urgently. Prompt treatment can often minimise the damage to the eye.
Who is at risk from a detached retina?
Although detached retina affects only about one person per 10,000, it is more common in middle-aged people and those who are very short-sighted. If you have a detached retina in one eye, the risk of developing one in the other eye is increased. Very rarely, younger people can have a weakness of the retina, or it can be detached as a result of a blow to the eye or head. Retinal detachment can also occur as a result of laser refractive surgery (LASIK) but this is a rare complication. Cataract surgery, ocular tumours and diabetic eye disease are other possible causes.
What can be done?
A detached retina needs urgent medical attention. The sooner the retina is reattached, the better the chances of regaining vision. With early help, it may only be necessary to have laser or freezing treatment. This is a simple procedure usually performed under a local anaesthetic. Often, however, an operation to repair the hole in the retina will be needed. This does not usually cause pain, but the eye will be sore and swollen afterwards. You will usually need to stay in hospital for two or three days after the operation.
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