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Age-related Macular DegenerationAge-related macular degeneration (ARMD) is the most common cause of vision loss in thoseaged over 50. It causes a gradual loss of central (but not peripheral) vision. Central vision isneeded for detailed work and for things like reading and driving. The disease does not lead tocomplete blindness. Visual loss can occur within months, or over many years, depending onthe type and severity of ARMD. There are two main types of ARMD - 'wet' and 'dry'. 'Wet'ARMD is most severe but more treatable. Visual loss caused by ARMD cannot normally bereversed. New drugs are an exciting development for wet ARMD as they may halt or delay theprogression of visual loss.

Understanding the back of the eye

Age-related Macular Degeneration (ARMD) symptoms and treatment | Pati... http://www.patient.co.uk/health/age-related-macular-degeneration

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The retina is made up of two main layers. There is an inner layer of 'seeing cells' called rods and cones. Thesecells react to light and send electrical signals down tiny nerve fibres (which collect into the optic nerve) to the brain.The outer layer - the retinal pigment epithelium (RPE) - is a layer of cells behind the rods and cones. The RPE isan insulating layer between the retina and the choroid. These cells help to nourish and support the rods and cones.They pass nutrients from the blood vessels in the choroid to the rods and cones. They also take waste materialsfrom the rods and cones to the blood vessels in the choroid. The RPE can be thought of as a filter, determiningwhat substances reach the retina. Many components of blood are harmful to the retina and are kept away from itby a normally functioning RPE.

The rods and cones are responsible for vision in different conditions. There are many more rods than cones, androds are smaller cells than cones.

The cone cells ('cones') help us to see in the daylight, providing the basis for colour vision.The rod cells ('rods') help us to see in the dark - 'night vision'.

The macula is a small but vital area of the retina at the back of your eye. It is about 5 mm in diameter. The maculais the part of the retina that is the most densely packed with rods and cones. The macula is essential for centralvision. In the middle of the macula is an area called the fovea, which only contains cones.The choroid is a layer of tissue behind the retina which contains many tiny blood vessels. These help to takeoxygen and nutrients to the retina.Bruch's membrane is a thin membrane which helps to form a barrier between the choroid and the delicate retina.The sclera is the outer thick white layer of the eye.

When you look at an object, light from the object passes through the cornea, then the lens, and then hits the retinaat the back of the eye. The light from the object focuses on the macula. You need a healthy macula for detailedcentral vision.

What is age-related macular degeneration?

ARMD is a condition that occurs when cells in the macula degenerate. This occurs with partial breakdown of theRPE and the cells become damaged and die. Damage to the macula affects your central vision which is neededfor reading, writing, driving, recognising people's faces and doing other fine tasks. The rest of the retina is used forperipheral vision - the 'side' vision which is not focused. Therefore, without a macula you can still see enough toget about, be aware of objects and people, and be independent. However, the loss of central vision will severelyaffect normal sight. There are two types - 'dry' and 'wet' ARMD - described below.

Who gets age-related macular degeneration?

ARMD is the most common form of macular degeneration and develops in older people. There are other rare


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types of macular degeneration which occur in younger people. ARMD can affect anyone. It is the most commoncause of severe sight problems (visual impairment) in the UK, and indeed in the developed world. It becomes morecommon with increasing age, as the name suggests. It is rare under the age of 60. If you develop ARMD in oneeye, you have a high chance (about 6 in 10) that it will also develop in the other eye.

About 1 in 100 people aged 65-75, and about 1 in 8 people aged over 85 have ARMD severe enough to causeserious visual loss. About twice as many women over the age of 75 have ARMD compared with men of the sameage.

The two types of age-related macular degeneration

Dry ARMDThis is the most common form and occurs in 9 in 10 cases. In this type the cells in the RPE of the maculagradually become thin (they 'atrophy') and degenerate. This layer of cells is crucial for the function of the rods andcones which then also degenerate and die. Typically, dry ARMD is a very gradual process as the number of cellsaffected increases. It usually takes several years for vision to become seriously affected. Many people with dryARMD do not totally lose their reading vision.

Wet ARMDWet ARMD may also be called neovascular or exudative ARMD. It occurs in about 1 in 10 cases. However, it islikely to cause severe visual loss over quite a short time - sometimes just months. Very occasionally, if there is ableed (haemorrhage) from a new blood vessel, this visual loss can occur suddenly, within hours or days. In wetARMD, in addition to the retinal pigment cells degenerating, new tiny blood vessels grow from the tiny bloodvessels in the choroid. This is called choroidal neovascularisation. The new vessels break through Bruch'smembrane and into the macular part of the retina. These vessels are not normal. They are fragile and tend to leakblood and fluid. This can damage the rods and cones, and cause scarring in the macula, causing further visionloss.

Both wet and dry ARMD are further classified according to severity. Early, intermediate or advanced types refer tothe degree of damage to the macula. 6 in 10 cases of intermediate/advanced ARMD are due to wet ARMD.

What causes age-related macular degeneration?In people with ARMD the cells of the RPE do not work so well with advancing age. They gradually fail to takeenough nutrients to the rods and cones, and do not clear waste materials and by-products made by the rods andcones either. As a result, tiny abnormal deposits called drusen develop under the retina. In time the retinal pigmentcells and their nearby rods and cones degenerate, stop working and die. This is the dry type of ARMD.

In other cases, something also triggers new blood vessels to develop from the choroid to cause the wet form ofARMD. The trigger is not known. It may be that some waste products which are not cleared from the RPE maystimulate new blood vessels to grow in an attempt to clear the waste.

The exact reason why cells of the RPE stop working properly in people with ARMD is not known. Certain riskfactors increase the risk of developing ARMD. These include:

Smoking tobacco.Possibly, high blood pressure (inconclusive evidence).A family history of ARMD. (ARMD is not a straightforward hereditary condition. However, your risk of developingARMD is increased if it occurs in other family members.)Sunlight. This has yet to be proven, but laboratory studies suggest that the retina is damaged by UVA and UVBrays (sunlight rays).

ARMD seems to be more common in people from Caucasian (white) racial backgrounds than from other racialgroups.

What are the symptoms of age-related macular degeneration?


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The main early symptom is blurring of central vision despite using your usual glasses. In the early stages of thecondition you may notice that:

You need brighter light to read by.Words in a book or newspaper may become blurred.Colours appear less bright.You have difficulty recognising faces.

One specific early symptom to be aware of is visual distortion. Typically, straight lines appear wavy or crooked. Forexample, the lines on a piece of graph paper, or the lines between tiles in a bathroom, or the border of any otherstraight object, etc.A 'blind spot' then develops in the middle of your visual field. This tends to become larger over time as more andmore rods and cones degenerate in the macula.Visual hallucinations are common in people with severe visual loss of any cause. Visual hallucinations (also calledCharles Bonnet syndrome) can occur if you have severe ARMD. People see different images, from simple patternsto more detailed pictures. The experience can be upsetting but is less frightening if you are aware that it canhappen in ARMD. Importantly, it does not mean you are developing a serious mental illness. If you do developvisual hallucinations they typically improve by 18 months but in some people they last for years.

ARMD is painless. Symptoms of dry ARMD tend to take 5-10 years to become severe. However, severe visualloss due to wet ARMD can develop more quickly.

Always see a doctor or optometrist promptly if you develop visual loss or visual distortion. This is not onlythe case if you are worried about ARMD. Other sight-threatening conditions can occur suddenly with visual loss,such as a detached retina. Peripheral vision is not affected with ARMD and so it does not cause total blindness.

Note: if the vision of one eye only is affected, you may not notice any symptoms, as the other good eye oftencompensates. When both eyes are affected you are more likely to notice symptoms. Older people should haveregular eye checks to check each eye separately for early ARMD (and to check for other eye conditions such asglaucoma).

How is age-related macular degeneration diagnosed?

If you develop symptoms suggestive of ARMD, your doctor or optometrist (optician) will refer you to an eyespecialist (ophthalmologist). This should be done urgently, especially if there is any suggestion of wet ARMD. Theophthalmologist may ask you to look at a special piece of paper with horizontal and vertical lines to check yourvisual fields. If you find that any section of the lines is missing or distorted, then ARMD is a likely cause of thevisual problem. The ophthalmologist will examine the back of your eye with a slit lamp microscope. This is amagnifying piece of equipment where the ophthalmologist examines your retinae through what look like binoculars.Digital photographs can be taken of the retinae. The ophthalmologist will look for the typical changes that occurwith dry ARMD and wet ARMD.

If wet ARMD is diagnosed or suspected, then a further test called fluorescein angiography may be done. Forthis test a dye is injected into a vein in your arm. Then, by looking into your eyes with a magnifier and takingpictures with a special camera, the ophthalmologist can see where any dye leaks into the macula from theabnormal leaky blood vessels. This test can give an indication of the extent and severity of the condition.

Another test called ocular coherence tomography is becoming more commonly used. This is a noninvasive testthat uses special light rays to scan the retina. It can give very detailed '3D' information about the macula, and canshow if the macula is thickened or abnormal. This test is useful when there is doubt about whether ARMD is thewet or dry form. It is also a useful test to assess and monitor the results of any treatment.

Is there any treatment for age-related macular degeneration?

For the more common dry ARMD, there is no specific treatment yet. There are, however, certain things that can bedone to maximise the sight you do have and to improve your eye health. Low vision rehabilitation and low visionservices are offered by hospital eye departments and information can be found from the Macular Disease Societyand the Royal National Institute of Blind People (RNIB). Stopping smoking and protecting the eyes from the sun'srays by wearing sunglasses are important. A healthy balanced diet rich in antioxidants may be beneficial, as may


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the addition of dietary supplements (see below for details). Remember that in this type of ARMD the visual losstends to be gradual, over 5-10 years or so.For the less common wet ARMD, treatment may halt or delay the progression of visual loss in some people. Newertreatments may even be able to reverse some of the visual loss. Treatments which may be considered includetreatment with anti-vascular endothelial growth factor (anti-VEGF) drugs, photodynamic therapy and laserphotocoagulation.

Anti-VEGF drugsIn recent years a group of drugs (medicines) called anti-VEGF drugs has been developed. Vascular endothelialgrowth factor is a chemical that is involved in the formation of new blood vessels in the macula in people with wetARMD. By blocking the action of this chemical, it helps to prevent the formation of the abnormal blood vessels thatoccur in wet ARMD. Anti-VEGF drugs are also called anti-angiogenic drugs meaning that they act againstsubstances that promote new blood vessel growth.

Anti-VEGF drugs include ranibizumab (Lucentis), pegaptanib (Macugen), and bevacizumab (Avastin). Othersare being developed but, due to the new technologies involved, these drugs are very expensive (estimated atbetween 2,000 and 9,000 per year per patient). The National Institute for Health and Clinical Excellence (NICE)appraised these therapies in August 2008 and gave approval to ranibizumab.

Ranibizumab (and other anti-VEGF drugs) are injected using a fine needle directly into the vitreous humour of theeye. Ranibizumab injections are needed every four weeks. But, very specific criteria have been set out by NICE todetermine which patients are eligible for treatment. The rationale is that new medicines, particularly very expensiveones, should only be given in circumstances where there is medical evidence for their effectiveness. Such evidencecomes from medical trials of drugs, comparing them with each other and with existing treatments. Anti-VEGF drugsare an exciting new development in the treatment of wet ARMD.

Ranibizumab will improve vision in about 1 in 3 people treated. However, treatment in most people will maintainvision and prevent the condition from getting worse. About 1 person in every 10 treated, will not respond at all.Clinical (drug) trials are ongoing and involve other anti-VEGF drugs but, at present, NICE does not recommendthem.

Photodynamic therapyThis is a technique that was developed in the late 1990s. A drug called verteporfin is injected into a vein in thearm. Within a few minutes the verteporfin binds to proteins in the newly formed abnormal blood vessels in themacula. A light at a special wavelength is then shone into the eye for just over a minute. Verteporfin is aphotosensitive drug. This means that when light is shone at the blood vessels coated with verteporfin, theverteporfin activates and causes damage, destroying the abnormally growing blood vessels (neither damaging thenearby rods and cones, nor any normal blood vessels).

Photodynamic therapy is only suitable for some cases. It depends on exactly where the new blood vessels aregrowing and their extent. It does not work in all cases although the success rate in treated people is high. Successmeans that the visual loss is prevented from getting worse - it does not restore any lost vision. Treatment usuallyneeds to be repeated every few months to continue to suppress newly growing blood vessels. The main advantagethat this method has over laser photocoagulation is that there is less damage to the normal retina.

Laser photocoagulationThis is a technique where a fine laser is 'fired' at the tiny new blood vessels that are forming. This destroys thedeveloping new blood vessels which helps to prevent the condition from getting worse. People undergoing thistreatment will develop a permanent black or grey patch affecting their vision and no sight is restored.

Laser photocoagulation is only suitable for a small number of cases. It depends on exactly where the new bloodvessels are growing, as the laser may also damage the rods and cones. New blood vessels growing very close tothe fovea may not be suitable because of the risk of severe visual loss arising from laser damage or scarring dueto laser treatment.

Other treatmentsTreatments such as radiation therapy, other drugs, and surgery to the retina are being investigated. For example, a


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surgical technique where a part of the peripheral retina is grafted into the diseased macular area is beinginvestigated. The value of these newer treatments is not clear. The treatment of macular degeneration is an activearea of research and treatment may well improve in the near future.

Diet, dietary supplements, and age-related macular degenerationCertain groups of people with ARMD (both wet and dry types) can benefit from vitamin and mineral supplements.These supplements can slow down the progression of ARMD. They are thought to be most beneficial in certaingroups of people, such as people with either advanced ARMD or with vision loss (due to ARMD) in one eye.Various products are available to buy over-the-counter (OTC). These supplements are not licensed medicines andgenerally are not available on prescription. Some primary care trusts (PCTs) may fund them, but have policies inplace, such that they can only be prescribed on specialist advice.

A specific combination of high-dose vitamins and minerals has been tested and found to be most effective. Themixture includes: vitamin C 500 mg, vitamin E 400 IU, beta-carotene (vitamin A) 15 mg (25,000 IU), zinc oxide 80mg and cupric oxide 2 mg daily. Only two products in the UK contain all of these, in the stated quantities -Viteyes Original and Bausch and Lomb PreserVision Original tablets. (Other marketed products, eg ICaps,contain similar constituents but either in different proportions, or with additional ingredients.)

There is some concern that the high doses of vitamins and minerals needed may lead to side-effects in somepeople. Certain vitamins are linked with specific diseases. Beta-carotene has been found to increase the risk oflung cancer in smokers, so these supplements are not advised in either ex-smokers or current smokers. Vitamin Ehas been linked with an increased risk of heart failure in people with diabetes or vascular (blood vessel) disease.Zinc may increase the risk of developing bladder and kidney problems. Because of these potential problems, youshould talk to your GP or ophthalmologist before starting these supplements.

Practical help

When your vision becomes poor, it is common to be referred (by your ophthalmologist) to a low vision clinic. Staffat the clinic provide practical help and advice on how to cope with poor and/or deteriorating vision.

Help may include:

Magnifying lenses, large print books, and bright lamps which may assist reading.Gadgets such as talking watches and kitchen aids which can help when vision is limited.Being registered as partially sighted or blind. Your consultant ophthalmologist can complete a 'Certificate of VisualImpairment'. You may then be entitled to certain benefits.

What else can I do?

If you smoke, try to stop. If you are are smoker, there are numerous health benefits to quitting. Smoking is a riskfactor for many illnesses, including ARMD. The NHS can provide help, support and medicines to assist stoppingsmoking. The NHS smokefree website provides further information on the services available.Eat a healthy balanced diet to try to make sure you get plenty of the types of vitamins that may help in ARMD.Stay safe with regards to driving. If you are registered with sight impairment you should not drive and should notifythe DVLA. The DVLA website ([url]www.dvla.gov.uk[/url]) provides detailed guidance on fitness to drive andminimum standards with regard to sight. This includes being able to read, wearing your normal glasses, a vehiclenumber plate at a distance of 20 metres.Consider regular sight tests as you get older. You should visit an optometrist every two years, even if there is nochange in your vision. An eye test can often pick up the first signs of an eye condition before you notice any changein your vision. Your optometrist can advise you how often you need to have an eye check-up, depending on yourgeneral health, age, family history and other medical conditions. Early detection of problems often allows moreeffective treatment.

Further help & information

Macular Society


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RNIB

References | Provide feedback

Further reading & referencesAge-related Macular Degeneration - Guidelines for Management[http://www.rcophth.ac.uk/core/core_picker/download.asp?id=1185&filetitle=Age%2DRelated+Macular+Degeneration+2009+Guidelines+for+Management%2Dupdate], Royal Collegeof Ophthalmologists (February 2009)The clinical effectiveness and cost effectiveness of photodynamic therapy for age related maculardegeneration[http://www.nice.org.uk/86772], NICE Technology Appraisal (Sept 2003)Pegaptanib and ranibizumab for the treatment of age-related macular degeneration[http://www.nice.org.uk/guidance/index.jsp?action=byID&o=12057], NICE Technology Appraisal Guideline (August 2008)Macular degeneration - age-related[http://www.cks.nhs.uk/macular_degeneration_age_related], Clinical Knowledge Summaries(March 2010)Chakravarthy U, Evans J, Rosenfeld PJ[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=20189972]; Age related macular degeneration. BMJ. 2010 Feb 26;340:c981. doi: 10.1136/bmj.c981.Evans JR. Antioxidant vitamin and mineral supplements for slowing the progression of age-related maculardegeneration. Cochrane Database of Systematic Reviews 2006[http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD000254/frame.html], Issue 2

Original Author: Dr Tim Kenny Current Version: Dr Katrina Ford

Last Checked: 23/08/2010 Document ID: 4860 Version: 42 EMIS

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medicalconditions. EMIS has used all reasonable care in compiling the information but make no warranty as to itsaccuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. Fordetails see our conditions.


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