GLAUCOMA

What is glaucoma?

Glaucoma is the name of an eye condition in which the optic nerve is damaged at the point where it leaves the eye. The eye needs a certain amount of pressure to keep its shape so that it can work properly. In some people, the damage is caused by raised eye pressure. Others may have an eye pressure within normal limits but damage occurs because of a weakness in the optic nerve.
The most common form of glaucoma is chronic glaucoma where eye pressure rises very slowly but there is no pain to show there is a problem. If untreated, over a period of time, the field of vision gradually becomes impaired. Chronic glaucoma is more common with increasing age. It is uncommon below the age of 40, affecting 1% of people over this age and 5% over 65. If you have a close relative who has chronic glaucoma, then you should have regular eye tests. This is especially important if you are age over 40.
Acute glaucoma is much less common. This happens when there is a sudden rise in eye pressure. It can be quite painful and will cause permanent damage to your sight if not treated properly.

How is glaucoma detected?

Tests for chronic glaucoma are carried out as part of a regular eye test. Recording shape of the optic nerve by use of Retinal Retinal Photography , measuring the eye pressure using one special instrument and testing your fields of vision with another, which shows a sequence of spots of light on a screen.
A sudden increase in eye pressure can be very painful. The affected eye becomes red and sight deteriorates. Vision may seem misty with coloured rings around white lights. There may even be nausea and vomiting.

How is glaucoma treated?

The main treatment for chronic glaucoma aims to reduce the eye pressure. It is usually started with eye drops but can involve a small operation to reduce the pressure. Immediate hospital treatment may be required with acute glaucoma.

Can glaucoma be cured?

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DIABETES

Estimates suggest that nearly one person in twenty five in the UK is affected by diabetes mellitus, a
condition which means that, due to a lack of insulin, the body cannot cope normally with sugar and other
carbohydrates in the diet. Diabetes can start in childhood, but more often begins in later life. It can cause complications which affect different parts of the body, the eye being one of them. There are two different types of diabetes
mellitus:

Type 1 diabetes, which can also be referred to as insulin dependent diabetes mellitus (IDDM). This type
of diabetes commonly occurs before the age of 30 and is the result of the body producing little or no
insulin. Type 1 is controlled by insulin injections.
Type 2 diabetes, which can also be referred to as non-insulin dependent diabetes mellitus (NIDDM).
This type of diabetes commonly occurs after the age of 40. In this type of diabetes the body does
produce some insulin, although the amount is either not sufficient or the body is not able to make proper
use of it. This type of diabetes is generally controlled by diet or tablets, although some people in this group will use insulin injections.

How can you avoid damage caused by Diabetes?

It is widely accepted that regular exercise and eating a healthy diet are ways you can help to reduce and avoid the impact of Diabetes. If you have diabetes this does not necessarily mean that your sight will be affected, but there is a higher risk. If your diabetes is well controlled then you are less likely to have problems, or they may be less
serious. However, if there are complications that affect the eyes then this may result in loss of sight.
Most sight loss due to diabetes can be prevented, but it is vital that it is diagnosed early. This can only be
detected by a detailed examination of the eye. Therefore, regular, annual eye examinations are
extremely important, as you may not realise that there is anything wrong with your eyes until it is too late.(Top)

CATARACTS

A Cataract is a clouding or hazing of the lens inside the eye.

The lens is a transparent body that lies just behind the pupil.

In the early stages of a cataract, only part of the lens becomes cloudy and symptoms include blurring of vision, glare, especially in bright sunlight, a dimming of colour vision and sometimes doubling of vision. Cataracts are extremely common as we get older and often form as part of the natural aging process, like greying of hair, although they can be due to diabetes, injury and certain drugs. There is some evidence that taking anti-oxidants such as vitamins A, C, E and selenium may prevent development of cataracts, but once the cataract has started it is unlikely that these will make any difference.

The only way to treat a cataract is by a small operation to remove the cloudy lens and replace it with a plastic lens, called a lens implant. Nowadays, it is a relatively simple procedure usually performed as a day case under local anaesthetic, which means you can go home the same day. With modern techniques, cataracts can be removed at any stage of their development, so you don’t have to wait for the cataract to become ripe or ready. Generally if you use the NHS there is , a waiting list for the operation. If you are happy to go privately we would recommend Advanced Visioncare.

When we examine your eyes and notice a cataract that is causing problems to your vision, we refer you to your GP, who will then recommend if it is appropriate for you to see an Ophthalmologist (eye doctor) who assesses your eyes and discusses the options available to you. (Top)

MACULA

What is it?

The macula is located at the back of the eye at the centre of the retina. It enables us to see fine detail and objects directly in front of us. It plays a vital role in helping people to read, write, drive and perform other detailed tasks. It also enables us to recognise faces and see colour.

There are two types of AMD: Dry AMD is the most common form of the condition. Cells in the retina fail to function properly as a person gets older. The cells don't take in enough vital nutrients and fail to clear by-products of cell functioning. This causes tiny abnormal deposits, called drusen, to be left under the retina, making it uneven.
In time, retinal cells degenerate and die causing sight loss. This occurs very gradually over many years.
Wet AMD accounts for 10 to 15 per cent of cases. It often develops quickly and is also known as 'neovascular AMD' because it involves the growth of new blood vessels behind the retina.
These new blood vessels are very fragile and so may leak fluid or blood. This results in scarring that causes rapid visual loss.
What causes it?
It's unclear what causes AMD. It becomes more likely as a person ages because, over time, the cells in the macula become damaged and worn out.
What are the symptoms?
Both eyes are usually affected, although one eye may be affected before the other. The good eye usually compensates for the affected eye and for many years this can disguise the fact that there’s a problem. There's no pain or redness of the eyes.
Because it's central vision that's affected, patients retain some residual vision, but this is at the periphery of their field of vision where images aren't in focus.
Any activity that requires detailed, clear vision is compromised, and in the late stages of the disease sight loss is so severe that patients are offered registration as partially sighted or blind.
Who's affected?
In developed countries, it's estimated that one in 50 people over the age of 50 and up to one in five people over the age of 85 have AMD.
A person is at greater risk of developing AMD if they smoke, have high blood pressure or have a relative with the condition.
What's the treatment?
Currently, there's no medical treatment for dry AMD. However, not smoking and eating a healthy diet may help to slow the rate of deterioration. High does of beta-carotene, vitamins C and E, and zinc may help to slow down visual loss for some people who already have AMD.
Additional lighting and magnifiers can help those with dry AMD to make better use of their residual sight.
Medical breakthroughs in the treatment of wet AMD mean that, in most cases, treatments can prevent further visual loss, and in some cases restore partial sight.
There are three types of treatment for wet AMD:

• Photocoagulation uses a hot laser to seal leaking blood vessels, but can only be used in a minority of cases where the leakage is not directly in the centre of the macula.
• Photodynamic therapy (PDT) uses a cold laser to seal leaking blood vessels. This involves injecting a drug that reaches and coats the abnormal blood vessels via the blood stream. The drug is then activated by shining a light at the coated blood vessels and it destroys them.
• Anti-vascular endothelial growth factor (anti-VEGF) treatments target a protein involved in the formation of new blood vessels. High levels of VEGF can cause proliferation of blood vessels and fluid leakage. The drugs are injected under the macula. The number of injections varies. In trials the injections were given either every four or every six weeks, but in practice clinicians have to decide on the most appropriate treatment regime based on their assessment of the patient's response to the drugs. Anti-VEGF treatments have been shown to halt sight loss and in some cases restore it. They may not be available on the NHS and are currently being reviewed by the National Institute for Clinical Health and Excellence (NICE).
• A new drug treatment for wet AMD, called anecortave acetate, aims to stop new blood vessels forming, but is injected behind the eye rather than into it. Currently, it's only at the experimental stage.
  Can it be prevented?
  Apart from the growing risk as people age, there appears to be a genetic influence that significantly increases the risk of developing AMD, particularly if other risk factors are present. While ageing and genetic predisposition can't be modified, other risk factors can.
  Smoking - people who smoke at least double their risk of developing AMD. The risk may be as high as 34 times that of a non-smoker if there's also a family history of AMD.
  When people stop smoking the risk decreases, but this can take up to 20 years so it's important not to start.
  Ultraviolet (UV) light - although it's thought that UV light doesn't reach the retina, and so doesn't increase the risk of developing AMD, wearing high-quality sunglasses in bright sunlight is recommended to protect eye health generally.
  Nutrition - the role of vitamins and minerals and antioxidants in helping to prevent AMD isn't clear. Some scientific evidence suggests a diet rich in antioxidant vitamins and minerals may help reduce the risk of a person developing AMD, although other studies suggest the scientific evidence isn't strong enough to recommend this.

However, a diet rich in antioxidant vitamins and minerals is unlikely to cause any harm. It makes sense to eat plenty of fruit and vegetables each day, particularly kale and leafy green vegetables. People with moderate AMD, should consult a doctor before taking additional amounts, especially high-dosage supplements.

Myopia (short-sightedness)

Myopia is commonly known as short-sightedness. It means that the eye is unable to focus on distant objects, making them seem blurred. Most forms of myopia are considered a variation from normal vision, rather than a medical condition.
Vision can usually be corrected with glasses or contact lenses, or, in some cases, with laser eye surgery.

How the eye focuses

The eye and myopia

Light coming into the eye is focused onto the retina - an area on the rear wall of the eyeball. Seventy per cent of light entering the eye is focused by the cornea (a clear dome which forms the outer covering of the pupil). The rest is focused by the lens, which sits behind the cornea.
If the light is focused properly on the retina, we see a clear image. If the light focuses in front of the retina, the image is fuzzy. See the illustration above.
With myopia, the cornea is too curved or the eyeball too long. This means that images are focused in front of the retina rather than directly on it.

Who gets myopia?

Myopia most commonly develops in childhood or early teens (between 8 and 14). The risk of developing myopia is increased if there is a family history of it. There may also be a link between myopia and prolonged close-up work, such as reading or sitting close to the television, although there is little scientific evidence for this.
Myopia can be associated with certain types of cataracts, where the lens becomes cloudy. It can also be caused by a condition called keratoconus, in which the cornea thins and becomes more curved.
Temporary short-sightedness, called pseudomyopia, can be caused by a number of diseases or certain drugs. For example, myopia may be the first sign of type-2 (non insulin-dependent) diabetes. Symptoms of pseudomyopia usually clear up if the underlying cause is treated.

Effects of myopia

To a short-sighted person, distant objects seem blurred, while near objects can be seen more clearly. Other symptoms can include headache and tired eyes.
Myopia develops as the eyeball grows, so it starts in childhood and may worsen during the teens. It normally stops getting worse in adults.
Children younger than eight may not realise they have blurred vision. Parents or teachers may suspect a child has myopia if they squint or frown a lot, hold books close to their face, or have trouble seeing a blackboard, television or cinema screen.

Another condition, long-sightedness (hyperopia), is a natural process of ageing. This may counteract the effects of mild myopia, so that some people with myopia find they can do without glasses for close work as they grow older. This is sometimes called "second sight". (Top)

HYPEROPIA (long-sightedness)

Hyperopia is a sight problem that affects your ability to see close-up objects. Commonly known as long-sightedness, the condition is a type of focusing error, and tends to get worse as you get older.
Sight problems are very common, and many people are either long or short-sighted. The percentage of people with hyperopia increases with age. A study has shown that 13.2% of people who are between 20-25 years of age have hyperopia. This increases to 17.4% for people who are between 40-45 years of age.
Many children are born with mild hyperopia which normally resolves itself as they grow older and their eyes develop.
It is thought that some cases of hyperopia may be inherited (run in families). A gene has been identified that causes a very rare form of extreme hyperopia. However, further research is needed into the possible genetic causes of the more common types of hyperopia.

Hyperopia can be easily corrected with glasses, contact lenses, or corrective surgery. Laser surgery is an increasingly popular surgical option, but it is not suitable for everyone.

Symptoms

Signs that you may have hyperopia include:

• objects that are close appear out of focus,
• you find you have to squint to see clearly,
• your eyes feel uncomfortable after an activity that involves close focusing, such as reading, writing, or working on a computer, and you experience pain or burning in or around your eye. (Top)

SQUINT

Introduction

A squint (strabismus) is a condition of the eye that causes one of the eyes to turn inwards (converge), outwards (diverge) or sometimes upwards, while the other eye looks forward.
The cause, severity, and direction of a squint varies from person to person. It is usually spotted in childhood, sometimes within weeks of a baby being born, and affects 5-8% of children (1-2 in every 30).

Symptoms

The most common symptom of a squint is one of the eyes not looking straight ahead. In newborn babies it is quite normal for their eyes to 'cross' occasionally, particularly if they are tired. However, if you notice that this happens to your child beyond three months of age, it is advisable to talk to your GP.
Your child may also look at you with one eye closed, or with their head turned to one side. These may be clues that they are experiencing double vision, and could be a sign that they have a squint.

Causes

There are different types of squint, and the cause is not always known. A baby can have a congenital squint (born with the condition), particularly if it runs in the family.
The squint can occur due to muscle or nerve problems in the eye, as a result of a childhood illness such as measles or chickenpox, or sometimes as a result of being long sighted (difficulty seeing close-up objects). When a child is very long sighted, their eyes will attempt to focus so much that double vision occurs. This can have a knock-on effect, causing one eye to turn away to avoid using it.

Treatment

A squint is a condition that should be treated as soon as possible after it's detected. Treatment is most effective in very young children. A squint will not disappear as the child gets older, and in fact the sight in the affected eye will gradually get worse.
There are several types of treatment available:

• If your child is long sighted, glasses may be prescribed which can often correct the long sight and the squint.
• Alternatively, a patch may need to be worn over the good eye, to encourage the eye with the squint to work harder and become trained to work properly.
• In some cases, the squint can be treated with special eye drops, or with eye exercises.

If none of these treatments help, then surgery may be required. Surgery for a squint involves moving the muscles attached to the outside of the eye to a new position. It may sometimes be necessary to operate on both eyes in order to 'balance' them effectively, even if the squint is only in one eye.
There is no chance of the child's eyesight being damaged by this operation, as the surgery does not touch the focussing part of the eye. When your child has returned home, they will need to use eye drops for a short time. The nurse will show you how to do this before you leave the hospital.

Complications