Macular degeneration is the leading cause of blindness and severe vision loss in the western world. While there is no cure it is possible to slow the progression of macular degeneration if detected early.
In New Zealand one in seven people over the age of 50 will experience macular degeneration (MD) in some form, with symptoms becoming increasingly common between the ages of 65 and 74.
However, some special forms of macular degeneration are not age-related and can occur at an earlier age. Diseases such as Stargardt’s disease and Best’s disease can also be a cause of macular degeneration. However the damage in these diseases is caused by a different process.
As the name suggests, MD occurs in the macula, the central part of the retina responsible for fine visual tasks like reading, writing or threading a needle. Age-related macular degeneration involves the wearing out of the macula and affects the central, fine vision.
Early symptoms of macular degeneration include difficulty reading (especially in dim light), distorted vision, a blurry spot in the central vision, difficulty focusing on intricate tasks and trouble picking up contrast or details.
Once a diagnosis of MD has been made a treatment plan can be created with the aim of preventing further damage to the patient’s vision. Treatment ranges from dietary and lifestyle changes through to the injection of medications into the eye.
Early detection of macular degeneration is key to preventing vision loss. While it is normal to experience changes to your vision as you age, not all vision issues should be dismissed as the natural aging process. Patients who seek early treatment have better outcomes than those who put off seeing an eye specialist.
Your eye specialist can detect macular degeneration before visual symptoms become obvious. For this reason, it is important to have regular eye tests.
The Amsler Grid is a simple test anyone can do to detect the early symptoms of macular degeneration. If the lines appear wavy, patches are missing, or there are dark spots on the grid, this can indicate macular degeneration.
Treatment of macular degeneration will depend on the level of degeneration. Your eye specialist will discuss the best options for you, which can range from lifestyle changes to medication to cold laser therapy known as Visudyne Photodynamic Therapy.
Can I see for myself if my retina or macula shows any signs of damage before I have symptoms?
No. It is impossible to examine your own retina, the light-sensitive lining at the back of the eye. You need to get a full eye examination from an eye specialist where the pupil is dilated, giving a clear view of the retina and macula.
Is macular degeneration painful?
No, it never causes physical discomfort as we are unable to feel any sensation from our retina. That’s why you need someone to check your retina – macular degeneration can occur without you being aware of any visual symptoms.
I suffer from watery or dry eyes. Does this mean I have the wet or dry form of macular degeneration?
The front of the eye gives us no indication of what happening at the back or vice versa. Symptoms such as bloodshot eyes, dry or itchy eyes and watery eyes have no relationship to the retina. Any disease or damage to the retina does not affect the front of the eye in any way.
Why don't new spectacles help?
Spectacles help our vision by ‘assisting’ the natural lens inside the eye to better focus the image onto our retina at the back of the eye. If the retina is damaged, as with MD, it cannot ‘take a good picture’ regardless of how strong the lens or spectacles are.
Do any other eye diseases such as cataract, glaucoma or diabetic retinopathy have an impact on MD?
No. Other eye diseases or complaints have no impact on the incidence, severity or outcome of macular degeneration. Of course, other eye conditions may also have impact on your vision, potentially adding to or exacerbating the visual problems caused by MD. However they do not affect the actual disease process.
Is it 'normal' to experience visual hallucinations?
It is common for people with severe MD, where most central vision is gone, to experience strange visual symptoms. It is the brain trying to make sense of or “fill in the gap” caused by the damage of MD. These symptoms can be mildly irritating or quite distressing – in the case of those who experience vivid, random images of everyday objects or scenes at the most inappropriate times. Be assured you are not going crazy – it just seems like it – and images often settle down with time. Please discuss your concerns with your eye specialist.
What is meant by ‘degeneration’?
When we use the term degeneration to describe something in the body, it means a gradual breaking down of tissues resulting in reduced function of the parts affected. We are all familiar with the medical term arthritis; it means the degeneration or wearing out of our joints. Likewise macular degeneration is a wearing out of our macula.
What other kinds of macular degeneration are there?
Age-related is the most common form of the disease, affecting those over 50 years of age. Younger people can get other special forms of macular degeneration and these are mainly inherited.
What are some examples of non age-related MD?
There are a number of other retinal diseases classified as dystrophies, including Stargardt’s disease and Best’s Macular Dystrophy.
These have a different disease process to macular degeneration and involve the retinal receptors, or cells, degenerating. Macular dystrophies are inherited and the majority are diagnosed before the age of 30 years.
My vision is good but my doctor says I have the early signs of MD - what does that mean?
Macular degeneration is a progressive disease. It begins in the special layer of cells known as the retinal pigment epithelium (RPE), which lies underneath the retina. Early changes can be detected by your doctor when they examine your eyes. These changes appear as drusen or pigment changes and suggest that you may go on to visual loss.
What is the difference between dry and wet MD?
Dry MD is more common qne 9 out of 10 patients with MD have the dry type. Dry MD varies in severity and rate of progression – so not all patients with dry MD will experience severe vision loss. In this condition there is slow degeneration and loss of the photoreceptors (cones) at the macula which leads to reduced vision. The progression of dry MD can be slowed by quitting smoking, dietary changes, or vitamin supplements.
Any patient with dry MD, even mild disease, can suddenly ‘convert’ to wet MD. It occurs in about 1 in 10 patients with dry MD. The mild damage occurring in dry MD can promote a healing response that causes new blood vessels to grow under the retina. Unfortunately, these abnormal blood vessels don’t help, and instead they leak and bleed causing swelling of the macula, hence the name ‘wet’ MD.
The change to wet MD occurs suddenly and the damage to vision occurs much more quickly – without treatment most people with wet MD will lose all central vision over the course of a year. However, early treatment with injections of anti-VEGF medication into the eye blocks the healing response and reduces swelling and bleeding of the macula, This is very effective at improving or stabilising vision.
I have had dry MD for years. Does this mean I'm going to get wet MD too?
The progression of macular degeneration is different in each person. Some people have only the dry form for decades and never develop the wet form. However, if you have the dry form, even if very mild, you are at risk of developing wet MD. This is why it is so important to use the Amsler Grid regularly to check for any changes that might indicate a change from dry to wet MD.
No one else in my family has MD. Why did I get it?
There is clearly a genetic component and your risk of MD is higher if there are other family members who have it. Much of MD research is focused on identifying the genes involved and figuring out why some people get it and others don’t. It appears some genes predispose to developing MD, whilst others can be protective, and your unique combination of these genes gives the overall risk of developing MD. Unfortunately, we don’t yet have all the answers to this question yet.
Factors other than family history/genetics also contribute to the development of MD. You may have developed it because of age or lifestyle factors such as diet, smoking, high blood pressure or exposure to ultraviolet light. Smoking is the biggest modifiable risk factor. Smokers are 3 times more likely to develop MD and tend to develop MD 10 years earlier than non-smokers.
For more information and support visit the Macular Degeneration New Zealand website at https://www.mdnz.org.nz/
Macular Degeneration New Zealand has a variety of information sheets on MD you can download or you can order them to be delivered for free – follow this link https://www.mdnz.org.nz/services-1-1