AMD

13/07/2011

Macular degeneration is a painless eye condition that leads to the gradual loss of central vision (the ability to see what is directly in front of you). Central vision is used while:

  • reading
  • writing
  • driving

Macular degeneration occurs when the macula (the part of the eye that is responsible for central vision) is unable to function as effectively as it used to.

Macular degeneration does not affect the peripheral vision, which means that the condition will not cause complete blindness. The peripheral vision, sometimes known as "side vision", is the outer vision.

Types of macular degeneration

There are two types of macular degeneration:

  • Dry macular degeneration (also called non-neovascular) affects the eyes gradually.
  • Wet macular degeneration (also called neovascular) can develop very quickly, and is more serious than dry macular degeneration.

Around 90% of cases of macular degeneration are dry.

How common is macular degeneration?

Macular degeneration most commonly affects people who are over 50, and is referred to as age-related macular degeneration (AMD). Around 30% of people who are over 75 have early signs of AMD, and about 7% have more advanced AMD.

For reasons that are not fully understood, AMD tends to be more common in women than in men. There are also a number of other factors, such as smoking, that can increase the risk of developing AMD.

Macular degeneration in young people is rare, and is usually caused by a genetic condition.

Outlook

Although AMD is the leading cause of visual impairment in the UK, almost everyone affected will have enough peripheral vision to continue their daily activities.

There is currently no treatment for dry macular degeneration, but techniques such as using magnifying lenses to read can help people to live with the condition. Dry AMD progresses slowly, over several years.

Wet AMD is more serious. It is estimated that around 70% of people with wet AMD will experience severe loss of vision within two years of receiving their diagnosis.

There are several treatment options available that can slow the progression of wet AMD and, in some cases, restore some of the lost vision. Treatment must be started as soon as possible.

Macula
The macula is a small spot at the centre of the retina. It is the part of your eye where incoming rays of light are focused.

Retina
The retina is the nerve tissue lining the back of the eye, which senses light and colour, and sends it to the brain as electrical impulses.

Genetic
Genetic is a term that refers to genes. Genes are the characteristics inherited from a family member.

Visual impairment
The term visual impairment refers to anyone who is blind or partially sighted, rather than those who are short-sighted (myopia), or long-sighted (hyperopia).

13/07/2011

Macular degeneration is not a painful condition. In fact, some people do not even realise that they have macular degeneration until their symptoms become more severe.

The main symptom of macular degeneration is blurring of your central vision. Your peripheral (outer) vision is not affected.

Loss of central vision

Central vision loss affects your ability to see fine detail and colours. In particular, it results in: 

  • loss of visual acuity: the ability to detect fine details, or small distances, for example when you read or drive
  • loss of contrast sensitivity: the ability to see less well-defined objects, such as faces, clearly. 

If you have macular degeneration, your central vision will still be blurred, even when you wear glasses.

Dry age-related macular degeneration

If you have dry age-related macular degeneration (AMD), it may take 5-10 years before your symptoms significantly affect your daily life.

Sometimes, if only one of your eyes is affected by dry AMD, your healthy eye will compensate for any blurring or loss of vision. This means that it will take longer before your symptoms become noticeable.

You may have dry AMD if you find that:

  • You need brighter light than normal when reading.
  • It is difficult to read printed or written text (because it appears blurry).
  • Colours appear less vibrant.
  • You have difficulty recognising people's faces.
  • Your vision seems hazy, or less well defined.

If you are experiencing any of these symptoms, you should make an appointment with your GP or optometrist (a healthcare professional who specialises in diagnosing vision problems and eye conditions).

Wet age-related macular degeneration

If you have wet AMD, the symptoms of blurred central vision appear more suddenly than they do in dry AMD. You may also experience other symptoms such as:

  • Visual distortions. For example, straight lines may start to appear wavy or crooked.
  • Blind spots. A blind spot usually appears in the middle of your visual field. The longer a blind spot is left untreated, the larger it will become. This is known as a central scotoma.

Seek immediate medical assistance if you experience any sudden changes in your vision, such as above.

It may be a sign that you have wet AMD, which needs to be treated as soon as possible to reduce the risk of permanent damage to your vision.

If you require immediate medical attention, you will either need to book an emergency appointment with an optometrist or visit your local hospital's accident and emergency (A&E) department.

About 70% of people with wet AMD have the condition in both eyes. If you only have wet AMD in one eye, you have a 10% chance every year of it developing in the other eye as well. After five years, there is a 40% chance that wet AMD will also develop in your other eye. 

13/07/2011

Macular degeneration is caused by a problem with the macula in your eye. The macula is the spot at the centre of your retina (the nerve tissue lining the back of your eye).

How your eyes work

Light rays travel through the lens (the transparent structure at the front of your eye) and form images on the retina. The retina is the light-sensitive tissue at the back of your eye that senses light and colour.

The retina passes electrical impulses to your optic nerve (which connects your eye to your brain). The optic nerve sends these impulses to your brain where they are converted into an image. This enables you to recognise the objects that you see.

The macula is a small spot at the centre of the retina. It is the part of your eye where incoming rays of light are focused. The macula plays an essential role in helping you to see things that are directly in front of you, and it is used for close, detailed activities, such as reading and writing. It is therefore a very important part of the retina. 

The retinal pigment epithelium (RPE) is a layer of tissue that surrounds the outer surface of your retina. The RPE passes nutrients to your retina, and helps remove waste products from your eye.

Macular degeneration in younger people

In very rare cases, macular degeneration affects younger people. This is sometimes known as "juvenile macular degeneration".

It is possible to have macular degeneration from birth. In younger people, the condition is almost always caused by an inherited genetic disorder.

There are a number of different inherited disorders that can cause juvenile macular degeneration. Possible causes include:

  • Best's disease: a quite mild type of macular degeneration, also sometimes known as Best's vitelliform retinal dystrophy.
  • Stargardt's disease: the most common type of juvenile macular degeneration, it can start in childhood or early adulthood.
  • Sorsby's dystrophy: a type of macular degeneration that often begins between the ages of 30-40 and causes some loss of vision.

Inherited conditions such as these are very rare, and age-related macular degeneration (AMD) is a far more common form of the condition.

Dry age-related macular degeneration

As you get older, the RPE that covers your retina starts to get thinner as it begins to break down. This means that your retina can no longer exchange nutrients and waste products as efficiently as it used to.

Waste products start to build up in your retina and form small deposits, which are known as drusens. A build-up of drusens, combined with a lack of nutrients, causes the light cells in your macula to become damaged and stop working.

If the light cells in your macula are damaged, your central vision will become blurry and less well-defined.

Wet age-related macular degeneration

Wet AMD often starts in the same way as dry AMD, as the RPE begins to break down. However, with wet AMD, tiny new blood vessels begin to grow underneath the macula.

It is thought that these vessels may grow in order to help the retina to get rid of the waste products that build up when the RPE deteriorates. However, the exact cause for the growth of these abnormal blood vessels is not known.

If the new blood vessels leak blood or fluid into your eye, they can cause the more serious symptoms of wet AMD to develop, such as visual distortion and blind spots.

Risk factors

A number of factors may increase your risk of developing macular degeneration. Some of these factors are listed below.

  • Age. The older you get, the more at risk you are of developing macular degeneration. The condition usually affects people over 50.
  • Gender. Macular degeneration is more common in women than it is in men.
  • Genetics. It is thought that a problem with a certain gene may play a role in macular degeneration. However, the specific genetic problem has not yet been identified. A gene is a unit of genetic material that determines your body's characteristics.
  • Smoking. Studies have shown that people who smoke or have smoked in the past are nearly four times more likely to develop AMD than people who have never smoked.
  • Sunlight. If you are exposed to lots of sunlight during your lifetime, your risk of developing macular degeneration may be increased. To protect yourself, you should wear sunglasses in bright sunlight.
  • Alcohol. It is possible that drinking more than four units of alcohol a day may increase your risk of having early AMD. One unit of alcohol is approximately half a pint of standard beer or lager, or one 25ml serving of spirits. 

Macula
The macula is a small spot at the centre of the retina. It is the part of your eye where incoming rays of light are focused.

Retina
The retina is the nerve tissue lining the back of the eye, which senses light and colour, and sends it to the brain as electrical impulses.

Blood vessel
Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

Genetic
Genetic is a term that refers to genes. Genes are the characteristics inherited from a family member.

Gene
A gene is a unit of genetic material that determines your body's characteristics.

13/07/2011

If you are experiencing the symptoms of macular degeneration, visit your GP or make an appointment with an optometrist (a specialist in the diagnosis and treatment of poor eyesight).

If there is a sudden change in your vision, visit your GP or your nearest accident and emergency (A&E) department.

Referral

If your GP or optometrist suspects that you have macular degeneration, you will be referred to an ophthalmologist. An ophthalmologist is a medical doctor who specialises in eye disease and its treatment.

Your appointment will usually be at an eye department in a hospital. If travelling by car, ask someone else to drive you because if you have macular degeneration your vision may not be good enough to drive. During the appointment, you may also be given eye drops that will make your vision blurry.

Eye examination

Your ophthalmologist will first carry out a routine check of your eyes. You will be given eye drops to enlarge your pupils. These take around half an hour to start working, and may make your vision blurry or your eyes sensitive to light. The effect will wear off after a few hours.

Your ophthalmologist will look at the back of your eyes where your retina and macula are located using a magnifying device with a light attached to it. They will look for any abnormalities around your retina.

The ophthalmologist will then carry out a series of tests in order to confirm a diagnosis of macular degeneration.

Amsler grid

One of the first tests involves asking you to look at a special grid, known as an Amsler grid. The grid is made up of vertical and horizontal lines, with a dot in the middle. You can see an example of an Amsler grid by visiting the Macular Disease Society website

If you have macular degeneration, it is likely that some of the lines will appear faded, broken or distorted. Telling your ophthalmologist which lines are distorted or broken will give them a better idea of the extent of the damage to your macula.

As the macula controls your central field of vision, it is usually the lines nearest to the centre of the grid that appear distorted.

Retinal imaging

As part of your diagnosis, your ophthalmologist will need to take pictures of your retinas to see what damage, if any, macular degeneration has caused. This will confirm the diagnosis and prove useful in planning your treatment. There are several different ways of taking pictures of the retinas.

Fundus photography

A fundus camera is a special camera that can be used to take photographs of the inside of your eye. The camera can capture colour stereoscopic (three-dimensional) images of your macular. Your ophthalmologist can then look at the different layers of your retina to see what damage, if any, has occurred.  

Fluorescein angiography

An angiography is a type of X-ray examination that creates detailed images of your blood vessels and the blood flow inside them. A special dye is injected into your blood vessels and pictures are taken that show any abnormalities inside them.

A fluorescein angiography may be done if your ophthalmologist suspects that you have wet age-related macular degeneration (AMD). The angiography can confirm which type of AMD you have.

During a fluorescein angiography, the ophthalmologist will inject a special dye, called fluorescein isothiocyanate, into a vein in your arm. Over the next 10 minutes they will use a magnifying device to look into your eyes, and they will take a series of pictures using a special camera.

These images will allow your ophthalmologist to see if any of the dye is leaking from the blood vessels behind your macula. If it is, this may confirm that you have wet AMD.

Indocyanine green (ICG) angiography

The technique that is used for an ICG angiography is the same as for fluorescein angiography, but the dye that you are injected with is different. Indocyanine green (ICG) is used as an alternative dye to fluorescein isothiocyanate. ICG may be used as it can highlight slightly different problems in your eyes.

Coherence tomography

Coherence tomography uses special rays of light to scan your retina and produce an image of it. This can provide your ophthalmologist with detailed information about your macula. For example, it will tell them whether your macula is thickened or abnormal in any way, and whether any fluid has leaked into the retina.

Macula
The macula is a small spot at the centre of the retina. It is the part of your eye where incoming rays of light are focused.

Retina
The retina is the nerve tissue lining the back of the eye, which senses light and colour, and sends it to the brain as electrical impulses.

Blood vessel
Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

X-ray
An X-ray is an imaging technique that uses high-energy radiation to show up abnormalities in bones and certain body tissue, such as breast tissue.

 

Visual acuity

You may hear your GP or eye specialist referring to your "visual acuity". This is a measure of your ability to detect fine details or small distances, and it is often used as a way to describe how good your vision is.

Visual acuity is made up of two figures. For example, your visual acuity may be described as ‘6/60’. This means that you can see from six metres, or less, what someone with normal vision can see from 60 metres away.

The World Health Organization (WHO) defines blindness as severe sight loss, where a person has a visual acuity of 3/60.

13/07/2011

Dry age-related macular degeneration

There is currently no cure for dry age-related macular degeneration (AMD). With dry AMD, the deterioration of vision is very slow. You will not go completely blind as a result of dry AMD, and your peripheral (outer) vision should not be affected.

Help is available to make tasks such as reading and writing easier. Getting practical help may improve your quality of life and make it easier for you to carry out your daily activities.

You may be referred to a low vision clinic. These clinics can provide useful advice and practical support to help minimise the affect that dry AMD has on your life. For example, things that may make it easier for you to carry out close, detailed work include:

  • magnifying lenses 
  • large print books
  • intensive (very bright) reading lights

In the future, there may be more treatment options for dry AMD. For example, one option currently being looked into is rheopheresis

Rheopheresis

Rheopheresis is a blood filtration process where some of your blood is drawn out through a needle in a vein in your arm and transferred to a special machine. The machine filters the blood and then returns it to your body. To filter all of your blood takes between two to three hours.

Some trials have shown that rheopheresis can improve the vision of people with dry AMD. However, further research is needed before the technique is proven to be both beneficial and safe.   

Wet age-related macular degeneration

There are a number of treatments that can help to stop the progression of wet AMD. In order for treatment to be effective, it is very important that wet AMD is treated as soon as possible. Once your sight has been lost, it cannot usually be restored. Some of the treatments that are available for this type of AMD are outlined below.

Photodynamic therapy

Photodynamic therapy (PDT) is a treatment that was developed in the 1990s. It involves having a light-sensitive medicine called verteporfin injected into a vein in your arm. The injection lasts around 10 minutes.

The verteporfin is able to identify the abnormal blood vessels in your macula (the part of your eye responsible for central vision). It attaches itself to the proteins in these blood vessels in your eye.

After 15 minutes from the start of the injection, a low-powered laser is shone into your damaged eye. It is shone over a circular area just larger than the lesion (wound) in your eye. This usually takes around one minute.

The laser is not powerful enough to cause any damage to your eyes, but the light from the laser is absorbed by the verteporfin and activates it. The activated verteporfin destroys the abnormal vessels in your macula without harming any of the other delicate tissue in your eye.

Destroying the blood vessels stops them from leaking blood or fluid, preventing the damage the vessels are causing to the macula. PDT therefore stops the macular degeneration from getting worse.

You may need to have this treatment every few months to ensure that any new blood vessels that start growing are kept under control.

Who can use PDT?

PDT is not suitable for everyone. It will depend on where the blood vessels in your eyes are growing, and how severely they have affected your macula.

PDT may be suitable if your visual acuity is 6/60, or better. This means that you can see from a distance of six metres what someone with normal vision can see from a distance of 60 metres. Around 20% of people with wet AMD can have PDT.

Side effects

The medicine that is used in PDT is called verteporfin. Verteporfin may cause some side effects including:

  • visual disturbances, such as decreased, blurred, hazy, or fuzzy vision, blind spots, flashes of light, black spots, or grey or dark halos 
  • pain from having the medicine slowly injected (infused), usually in your back
  • skin reactions, similar to sunburn, following exposure to sunlight, usually within 24 hours of treatment 

Anti-VEGF medication

Anti-VEGF medication, eg Ranibizumab whose brand name is Lucentis, is a newer type of treatment that can also help to stop the progression of wet AMD.

VEGF stands for "vascular endothelial growth factor". It is one of the chemicals that is responsible for the new blood vessels that form in the eye as a result of wet AMD. Anti-VEGF medicines work by blocking this chemical and stopping it from producing the blood vessels.

The anti-VEGF medication has to be injected into your eye using a very fine needle. You will be given a local anaesthetic (a painkilling medication) so the procedure does not hurt. 

Anti-VEGF medication is primarily used to stop wet AMD from getting worse. However, in some cases anti-VEGF medicines have also been shown to restore some of the sight that may have been lost as a result of macular degeneration. It is important to be aware that your sight will not be restored completely, and not everyone will experience an improvement

Studies show that ranibizumab can help slow loss of visual acuity in over 90% of people, and may even increase visual acuity in around a third of people.

 

Side effects

Ranibizumab can cause some side effects. Around 10% of people may experience some of the following side effects:

  • bleeding from your eye
  • pain in your eye
  • inflammation or irritation
  • inflammation of your eyelids (blepharitis)
  • feeling like there is something in your eye
  • increased pressure in your eye
  • dry eye
  • vitreous floaters: small pieces of debris that float in the vitreous humour (a clear, jelly-like substance) in the middle of your eyeball
  • headache
  • joint pain
  • a common cold

The following side effects are less common, occurring in 1% of people or less:

  • cataracts(cloudy patches over the lens in your eye)
  • damage to your retina (the nerve tissue that lines the back of your eye) 
  • nausea (feeling sick) 
  • a cough
  • allergic skin reactions such as a rash, redness, or itchiness
  • anxiety
  • anaemia (having a reduced number of red blood cells).

Before it is prescribed, your ophthalmologist will discuss the risks that are associated with ranibizumab with you.

Vitamins and minerals

Some research has found that high doses of the vitamins A, C, E, and beta-carotene, and the mineral zinc, may be beneficial in slowing down the progression of AMD.

Although vitamin and mineral supplements are available in pharmacies and other retailers, you should only take those that your GP or ophthalmologist recommends. High doses of these vitamins and minerals can result in side effects and, if they are not taken at the correct dosage, they may do more harm than good.

For example, vitamin E may increase the risk of heart failure in people who already have certain heart conditions or diabetes (a long-term condition caused by too much glucose in the blood). Also, beta-carotene may increase the risk of lung cancer in people who smoke.

Further scientific research into the effects of vitamins and minerals on AMD is needed before their effectiveness can be definitively proven. Currently, there is not enough evidence to suggest that certain vitamins or minerals may prevent or delay the onset of AMD.

Possible treatments

The treatments described below have been used in the past to treat AMD, or they are currently being investigated. They may not be as effective, or as safe, as those described above, and may only be available with special arrangements for clinical guidance, for example as part of a clinical trial (research to test one treatment against another).

Implanting lens systems

For people with advanced AMD (dry or wet), it may be possible to implant an artificial lens system into your eye. The lens is the clear part at the front of your eye that focuses the light coming in. Under local anaesthetic, your lens is removed and replaced with a series of artificial lenses.

One initial trial has suggested that this may improve the vision in up to 67% of people. The long-term effects are not yet known.

Macular translocation

Wet AMD can be treated using a surgical procedure that is known as macular translocation. The procedure involves cutting out the macular and moving it to a new location. This is done by cutting around the edge of the retina and rotating it. The macular is then repositioned on an area that is not affected by the lesion (wound) and scars that are caused by wet AMD.

Macular translocation is a very complex surgical procedure, and while it can improve the vision of some people, severe complications are possible. Therefore, you are unlikely to be offered this treatment, although future trials may reconsider its use.

Laser photocoagulation

In the past, lasers have been used to treat wet AMD. Lasers are shone into the eye to coagulate (make solid) the abnormal vessels that have formed there. This stops the vessels leaking.

The procedure itself can permanently damage the vision and the condition tends to reoccur after treatment. Laser treatment has now been replaced with photodynamic therapy and anti-VEGF medication.

Macula
The macula is a small spot at the centre of the retina. It is the part of your eye where incoming rays of light are focused.

Retina
The retina is the nerve tissue lining the back of the eye, which senses light and colour, and sends it to the brain as electrical impulses.

Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Blood vessel
Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

Tissue
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.

Alternative anti-VEGF medications

Bevacizumab (brand name Avastin)

Bevacizumab is mainly used in the treatment of some types of cancer. It is not licensed for the treatment of wet AMD. However, it may still be used privately by some ophthalmologists.

 

The ophthalmic team

  • An optometrist (previously known as an ophthalmic optician) examines eyes and tests sight, as well as prescribing and providing spectacles and contact lenses. Optometrists are trained to recognise sight defects and eye diseases and some prescribe treatment for common eye conditions.
  • An ophthalmic medical practitioner(OMP) is a medical doctor who specialises in eye care. They examine eyes, test sight, diagnose abnormalities, and prescribe corrective lenses.
  • An ophthalmologist is a medical doctor who specialises in eye disease and its treatment or surgery. They mainly work in hospitals and hospital eye departments.
  • A dispensing optician fits prescriptions for spectacles provided by optometrists, OMPs, or ophthalmologists. They may also fit contact lenses after undergoing specialist training. A dispensing optician does not carry out eye examinations.
  • An orthoptist specialises in problems relating to eye movements and how the eyes work together. For example, they help to identify and treat squints, lazy eyes, and double vision.
  • An ophthalmic nurse is a nurse who has skills in eye care. Ophthalmic nurses work in hospital eye departments.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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