Age-related macular degeneration can be called different things by different people. Some call it macular degeneration alone. Some call it macular disease. Sometimes it’s called geographic atrophy, and sometimes it’s called exudative or atrophic macular degeneration. All of these are different terms or different forms for the same disease.
Age-related macular degeneration (AMD) is a leading cause of vision loss in people aged 50 and older. It affects the macula, the central part of the retina responsible for sharp, straight-ahead vision needed for activities like reading and recognizing faces. Though AMD doesn’t cause total blindness, its impact on central vision can significantly affect daily life.
The macula is a small, oval-shaped area in the centre of the retina, the light-sensitive tissue at the back of the eye. It is densely packed with photoreceptor cells, especially cones, which are responsible for colour and fine detail. When light enters the eye, the macula plays a crucial role in capturing this light to produce clear, detailed images.
Without a healthy macula, performing tasks requiring sharp vision becomes difficult. Peripheral vision remains unaffected in AMD, which is why people with the condition don’t experience total blindness.
Macular degeneration is a very common condition, especially in older adults. In fact, it is one of the leading causes of vision loss worldwide. Globally, approximately 196 million people were living with AMD in 2020, and this number is projected to increase to 288 million by 2040. AMD is relatively uncommon in the 50-59 age group, affecting about 2–3% of individuals. The prevalence increases to about 5–10% in 60-69 year-olds. The likelihood rises significantly, with up to 30% of people over 75 having some degree of AMD.
In its early stages, AMD might not show noticeable symptoms, especially in the dry form. In the early stages, the optician may notice drusen in the retina.
These are very fine particles of lipid and protein that can show up as yellow deposits. As the disease progresses, common symptoms include:
Several factors increase the risk of developing AMD:
+ Age:
The risk increases significantly after age 50, with the likelihood rising as you age.
+ Genetics:
A family history of AMD can elevate your risk. Researchers have identified certain genetic markers associated with a higher likelihood of developing the disease. A prominent one is a gene for complement factor H.
+ Lifestyle Factors:
+ Race:
Caucasians are more likely to develop AMD than other races. African or Asian patients can develop another form of the condition called polypoidal choroidal vasculopathy.
+ Cardiovascular Health:
High blood pressure, high cholesterol, and cardiovascular disease can increase the risk.
An Amsler grid is a simple tool that helps detect changes in your central vision. It’s particularly useful for monitoring conditions like macular degeneration, as it can reveal early signs of distortion or vision loss that you might not notice otherwise.
The grid consists of a square with evenly spaced horizontal and vertical lines. A central dot helps focus your vision during the test. By using the grid regularly, you can track changes in your eyesight and alert your doctor to any problems early.
If you see any distortions, missing areas, or other abnormalities, contact your eye doctor promptly. These could be early signs of changes in your retina or macula.
Early detection of wet (or exudative) AMD is critical to preserving vision. Eye care professionals use several tools and tests to diagnose AMD:
+ Comprehensive Eye Exam:
The doctor examines the retina and macula for signs of drusen or other abnormalities.
+ Optical Coherence Tomography (OCT):
A non-invasive imaging test that produces cross-sectional images of the retina, helping detect abnormalities. This test can be done through an undilated pupil and does not require any patient preparation. The test provides incredible amounts of detail about the centre of the retina and can be very accurate in diagnosing wet and dry macular degeneration.
+ Fluorescein Angiography:
A dye is injected into a vein, and photographs of the retina are taken to detect abnormal blood vessel growth.
+ Optical coherence tomography angiography (OCTA):
This is a relatively new test that can give the same detail as fluorescein angiography but without the need to inject dye into a vein. It also has the advantage of being done instantly and does not require patients to wait around to have later photographs of their eye.
There is a great deal of conflicting advice online about the different types of macular degeneration. This is my chance to dispel some of the myths so that things are clearer for you. All macular degeneration starts off as dry and this is the type of macular degeneration in the great majority of patients. In a small minority of patients, the dry macular degeneration will develop some wet macular degeneration on top. Let’s go through the different forms of dry and wet macular degeneration.
In this type of wet macular degeneration, abnormal blood vessels grow from the choroid into the retina. The choroid is the supporting structure that helps feed the retina oxygen and remove waste chemicals. It is normally separated from the retina by a barrier at the level of the retinal pigment epithelium. When this barrier is compromised in some way, usually due to the development of dry macular degeneration as outlined above, these blood vessels can grow from the choroid into the retina. The blood vessels can bleed and cause leakage of fluid in the retina and this causes the development of wet macular degeneration. As a result, the vision can be affected very quickly and without treatment patients are at risk of visual loss. In the past we used to talk about different types of choroidal neovascularisation such as classic or occult. This was important as they required different treatment strategies. The distinction is not important anymore as both types of choroidal neovascularisation are treated with anti-VEGF eye injections.
RAP lesions (also termed type 3 lesions) are where abnormal blood vessels grow from within the retina itself. These vessels can bleed or they can leak fluid directly into the retina. As a result, the vision can become very blurred as the very fine and fragile photoreceptor cells of the retina are compromised. RAP lesions can be very sensitive to treatment with anti VEGF injections and treatment for these is therefore also advised.
This condition is where polyps or little balloons form within the blood vessels of the choroid under the retina. It is not clear why this happens but the condition does seem to be more common in Asian and African patients. As with blood vessels growing into or inside the retina, these polyps can bleed or can leak fluid causing damage to the retina. It is thought that the risk of very large bleeds is greater in this type of wet macular degeneration. As before the distinction between this type of wet macular degeneration and other types is now not so important. The reason for this is that polypoidal disease is generally very sensitive to treatment with anti VEGF injections. In some patients using a cold laser (known as photodynamic therapy) can reduce the frequency of injections but injections do remain the mainstay of treatment.
These are lipid and protein particles that develop under the retina in patients with macular degeneration. When these are small they may be a part of natural normal eye development. Small drusen is defined as being under 63 microns in size. As drusen get bigger it becomes medium drusen and this is defined as being 63 microns to 125 microns in size. As drusen become larger still or small drusen coalesce they can form large drusen which is defined as being more than 125 microns in size. The reason this is important is because patients with intermediate or large drusen show a greater risk of disease progression but also benefit from taking AREDS2 supplements to reduce the likelihood of progression to advanced macular degeneration. Advanced macular degeneration is defined as either wet macular degeneration or geographic atrophy.
Anti-VEGF therapy is the gold standard treatment for wet AMD. VEGF stands for vascular endothelial growth factor, a protein that promotes the growth of abnormal blood vessels. Anti-VEGF medications inhibit this protein, reducing the growth of leaky blood vessels and stabilising vision.
Anti-VEGF eye injections have transformed the treatment of wet (exudative) macular degeneration. Before the advent of injections, patients typically lost vision from wet macular degeneration. In most patients, Anti-VEGF injections not only show stabilisation of vision but also can improve vision with treatment.
Although the thought of eye injections sounds concerning most patients typically say that the thought of the procedure is much worse than the reality. Patients are sat in a reclining bed and lots of anaesthetic and antiseptic is added to the eye. A very fine needle is used to inject the drug into the eye and this takes about a second. The needle comes in from the side so the patient is never able to see the needle.
Common anti-VEGF medications include ranibizumab (Lucentis), aflibercept (Eylea) and faricimab (Vabysmo). This newer option targets both VEGF and Ang-2 proteins, aiming for better durability. All these agents produce relatively equal results the newer agents have longer durability which means they can be given less frequently.
Patients typically need three to four injections spaced monthly to begin, after which the interval between injections increases to 2, 3 or even four months. The first three to four injections are the loading phase and these are where there can be a significant gain in vision. After this the injections are used to maintain the vision at this level. Injections stabilise or improve vision in most patients and halts disease progression in over 90% of cases.
Side effects include mild discomfort after the injection. Rarely, serious complications like infection (endophthalmitis) or retinal detachment can occur.
The treatment of AMD depends on its type and severity:
+ Lifestyle Changes:
Healthy habits play a key role in slowing the progression of dry AMD and maintaining eye health.
+ Nutritional Supplements (AREDS2 Formula):
For patients with medium or large drusen, studies have shown that specific vitamins and minerals can slow disease progression. This is known as the AREDS2 formula (Age-Related Eye Disease Study). This includes Vitamin C (500 mg), Vitamin E (400 IU), Lutein (10 mg), Zeaxanthin (2 mg), Zinc (80 mg as zinc oxide) and Copper (2 mg as cupric oxide). The AREDS2 formula reduces the risk of progression to advanced AMD by about 25% in eligible patients. It is recommended for people with medium or large drusen. They are available commercially as Maculshield Gold or Actase.
+ Monitoring Vision:
Regular monitoring helps detect changes early and allows for timely intervention.
+ Regular Eye Exams:
Schedule check-ups with your eye doctor as advised. This ensures any progression is closely monitored.
+ Low Vision Aids:
If dry AMD has caused significant vision loss, specialised devices can help you maintain independence and perform daily tasks.
Though AMD poses challenges, many strategies can help maintain independence and quality of life:
+ Low Vision Aids:
Magnifying glasses and electronic readers. Voice-activated devices for reading or navigation.
+ Environmental Adjustments:
Good lighting to reduce strain. High-contrast materials for better visibility.
+ Glasses:
These should be kept up to date and reviewed at least every two years as eyes change with time it is important that they are cleaned regularly and any repairs to the glasses are performed correctly.
+ Cataract Surgery:
Cataract is very common in older people and commonly coexists with macular degeneration. Before embarking on cataract surgery it is important that patients are informed that cataract surgery does carry a guarded prognosis due to macular disease. Nevertheless, the improvement in vision can be very significant if there is a significant amount of cataract. In the case of wet macular degeneration, it is wise to perform cataract surgery once the condition is stabilised and this usually means after the first three to four injections.
+ Support Networks:
Joining support groups or counselling can help individuals and families cope with vision loss. Depression can be common in patients with macular degeneration and joining support groups can help patients feel less isolated and alone. It is important to understand that macular degeneration does not stop people leading full independent lives but sometimes patients will need some adjustments in order to complete certain tasks.
If a patient’s vision becomes worse than a certain level they become eligible for registration as sight impaired or severely sight impaired. This isn’t mandatory but it can be very useful for patients to receive this certification as it opens up services to them that would normally be difficult to obtain. These services include things like help at home to remain as independent as possible or in the case of severe sight impairment it includes things such as a disabled badge or financial benefits to help patients remain independent.
The Royal College of Ophthalmologists and the Macular Society recommend that every eye clinic in the UK have an eye clinic liaison officer (ECLO). These are special people who are tasked with helping those with reduced vision maintain their independence and manage with their reduced vision. They are very good at helping patients get in touch with supporting societies and in liaising between different healthcare practitioners looking after a patient.
Ongoing research holds promise for more effective treatments and prevention strategies. Innovations include:
There are now two new forms of treatments for dry macular degeneration. These remain at an early stage and I would recommend patients keep their eyes peeled for developments in the near future:
Age-related macular degeneration is a complex condition that significantly impacts vision and quality of life. However, with early detection, effective management, and lifestyle adjustments, individuals can retain their independence and adapt to the challenges of AMD. Regular eye exams and proactive care remain the cornerstones of AMD prevention and treatment.
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