As its name suggests, macular degeneration results from the deterioration of the macula , a small area of the retina located at the back of the eye , near the optic nerve. It is from this part of the retina that the best visual acuity comes. Macular degeneration leads to a progressive and sometimes significant loss of central vision , which becomes increasingly blurred.
Macular degeneration mainly affects people aged 55 and over. It is referred to as age-related macular degeneration or AMD . There are various ways to slow the progression of age-related macular degeneration.
There is also a hereditary form of this disease, which is transmitted by genes: Stargardt’s disease . It occurs during childhood or adolescence. In this card, it will not matter.
Causes of Macular degeneration
A set of factors can cause macular degeneration. The age is the biggest risk factor. About 1 in 7 people aged 55 to 64 years is reached, and 1 in 3 in people 75 and over . People with a family history of macular degeneration are more likely to be affected.
The habits are important. The smoking is a major risk factor compared to non-smokers, smokers are 2 to 3 times more risk of one day suffering from this disease . Moreover, anything that impedes blood flow to the tissues of the eye increases the risk. This is the case of hypertension and hypercholesterolemia .
In an epidemiological study of 1,113 women aged 55 to 74, people who ate well, did not smoke and were physically active were 3 times less at risk of macular degeneration than those who adopted the less good habits of life . The impact force of lifestyle could vary from one individual to another, depending on the hereditary baggage .
Finally, inflammation could contribute to the onset of the disease. Indeed, researchers have found a correlation between blood levels of C-reactive protein , a marker of inflammation, and macular degeneration .
Types of Macular degeneration
- Age-related dry macular degeneration. Also referred to as age-related atrophic or non-neovascular macular degeneration , it is the least severe and most common form of macular degeneration. It evolves over several years. Age-related macular degeneration begins with the dry form before evolving in about 1 in 10 people into the wet form.
- Wet macular degeneration related to age. Also called exudative or neovascular, this form of macular degeneration is an aggravation of the dry form. It is characterized by the formation of new blood vessels in the choroid, under the retina. Blood or other fluids can escape and further damage the macula. It causes vision loss faster than the dry form, sometimes within days or weeks. The wet form can lead to complete loss of central vision. It is not clear what causes the formation of these blood vessels.
|A problem of visual pigments
Light enters the eye through the lens. The light rays end up on the retina, a thin membrane that covers the inside of the eye. The retina is composed of photoreceptor nerve cells, among others: cones and rods . These cells are needed to see well because they respond to colors and light intensities. It is in the macula, a small area in the center of the retina, that visual acuity is the most accurate. The macula allows central vision.
People with macular degeneration have small yellowish lesions in their macula called drusens or druses. These are transformed into scar tissue. This phenomenon is the result of poor elimination of visual pigments , photosensitive substances located in the photoreceptor cells. Normally, these pigments are eliminated and are constantly renewed. In affected people, they accumulate in the macula. As a result, blood vessels are less able to irrigate the macula. After a while, the view becomes altered.
In the case of the dry form , many people will still have a good vision all their life or will gradually lose their central vision. This form of macular degeneration is incurable. On the other hand, one can slow down its evolution by taking certain antioxidant vitamins and the practice of physical exercise. Since the disease may remain asymptomatic for a long time, this could delay diagnosis and therefore treatment – which may reduce its effectiveness.
In the case of the wet form , subjects may lose their central vision quickly. Fortunately, there are treatments to cure the wet form. This form causes symptoms fairly quickly: a sudden drop in vision and a distortion of objects (straight lines become distorted).
For both forms of age-related macular degeneration, vision can drop in one eye and stay in the other for years.
This disease never causes to total blindness since peripheral vision remains intact.
Symptoms of Macular degeneration
At first asymptomatic, the disease evolves to give rise to symptoms that vary according to the severity of the disease, but do not cause pain.
- A need to increase the light intensity for reading or for precision work.
- A central vision increasingly blurred or tangled , which is more noticeable in reading.
- Slow adaptation after glare from bright light or when brightness suddenly drops.
- An altered perception of colors : they appear duller and difficult to distinguish.
- A distortion of straight lines in cases of wet macular degeneration, near and far.
- At the most advanced stage, a small dark spot in the center of the visual field, a difficulty in recognizing faces and, sometimes, visual hallucinations (geometric shapes, animals, deformed faces, etc …).
People at risk
- People 55 and over .
- People who have already suffered from a vascular disorder , such as myocardial infarction, angina attack, or stroke . These problems are often related to a narrowing of the opening diameter of the arteries due to cholesterol deposits and other substances on the wall (atherosclerosis). In these people, the small blood vessels of the retina are probably affected by the same phenomenon: the retina is thus less well supplied with blood.
- People who have a family history of macular degeneration. If you are a first-degree relative of a person with wet-type macular degeneration, you are 3 times more likely to become a victim in turn.
- The women . The disease is slightly more prevalent in women than in men. As they live longer, they are more likely to be affected in their lifetime.
- People with clear eyes .
- The Caucasians .
Risk factors for Macular degeneration
- High blood pressure.
- Obesity may worsen age-related macular degeneration.
- Prolonged exposure to the sun’s ultraviolet rays without eye protection, but this is a hypothesis that remains to be verified.
Prevention of macular degeneration
|Eye exam. The Amsler grid test is part of a complete eye examination by an optometrist. The grid of Amsler is a squared array in the center of which is a point. It allows to evaluate the state of the central vision. The central point of the grid is fixed with one eye: if the lines appear hazy or deformed, or the central point is replaced by a white hole, it is a sign of macular degeneration linked to age .
In case of early diagnosis of the disease, it may be advisable to do the Amsler grid test once a week and inform your ophthalmologist of any change in vision. It is possible to do this very simple test at home by doing the test on the screen, by printing the grid, or by using a simple grid sheet whose lines are dark.
The frequency of the recommended eye examination varies according to age:
People who are at higher risk of visual impairment, for example because of a family history, may be required to undergo an eye exam more frequently.
If the vision changes, it is better to consult without delay.
|Basic preventive measures|
This helps prevent the onset and progression of macular degeneration. Smoking affects blood circulation, including in the small vessels of the retina. Also avoid exposure to second-hand smoke.
Adapt your diet
Exercised regularly, physical exercise improves and protects cardiovascular health, which also helps prevent macular degeneration.
In addition, for people who already have age-related macular degeneration, more than 3 times a week of moderate-intensity exercise , such as brisk walking, jogging or cycling, slows the progression of about 25% disease .
Take care of your health problems
Follow your treatment carefully if you have high blood pressure or high cholesterol.
Medical treatments for macular degeneration
Unfortunately, the damage already done to the macula is mostly irreversible. That’s why it’s important to detect macular degeneration as early as possible. Thus, it allows to preserve a maximum of vision.
For the dry form
No intervention can treat this form of the disease. That said, taking antioxidant vitamin supplements can slow down its progression. (These vitamins have no preventive effect if one does not have the disease.) Since the publication of the results of the AREDS study (see below), in 2001, doctors recommend to their patients with degeneration dry macular take daily a supplement that contains antioxidant vitamins, minerals and other antioxidant substances, such as lutein. They can be found in pharmacies, for example: ICaps, Macuvision, Ocuvite PreserVision, Super Vision and Vitalux Areds.
Research is underway to improve the treatment of dry macular degeneration. For example, clinical trials have evaluated the value of using low-intensity laser therapy to slow progression. This method has unfortunately proved ineffective.
Various adaptation measures (adapted glasses, magnifying glasses, etc.) help to improve daily functioning.
|The AREDS study
The AREDS study, for Age Related Eye Disease Study , covered 3,640 subjects aged 55 to 80 years. These were followed for more than 6 years. The results indicate that daily supplementation with 500 mg vitamin C, 400 IU vitamin E, 15 mg beta-carotene and 80 mg zinc oxide slows the progression of age-related macular degeneration. about 25% compared to placebo .
This beneficial effect has been observed in people suffering from a moderate or advanced form of degeneration. It should be noted that the doses of zinc (80 mg per day) given to participants in this long-term trial far exceed the maximum intake set by US and Canadian authorities (40 mg). This study was funded by the National Institutes of Health in the United States.
These positive results led to the marketing of various antioxidant supplements to preserve vision. Their content is similar to that of the preparation used in the AREDS study, but they contain smaller amounts of vitamins and minerals than the original preparation. Some do not contain beta-carotene since it is contraindicated for smokers to take as a supplement. For more information, talk to a health professional.
For the wet form
Antiangiogenic drugs . Recently used in the treatment of age-related macular degeneration, these medications ( Macugen, Lucentis) obtained on prescription prevent the formation of new blood vessels under the retina. These new vessels can damage the macula. In many cases, these drugs improve vision. They are injected directly into the eye, ideally every month. A new antiangiogenic drug is now available: Avastin. A study published in 2011 that lasted 1 year indicates that Avastin has an efficiency comparable to that of Lucentis.
Photodynamic therapy. As part of this procedure, a light-reactive drug (Visudyne) is injected into a vein and concentrated in the new vessels beneath the macula. Then the ophthalmologist directs a cold laser beam on the macula. The drug will then release some substances that will destroy these vessels. This, however, causes a slight loss of vision. This method is being used less and less, as antiangiogenic drugs often offer better results. Studies are underway to assess the value of combining an antiangiogenic drug (Lucentis) with photodynamic therapy.
Photocoagulation of laser lesions. It consists of destroying the abnormal vessels by sealing them with a high-intensity laser. This intervention is not without risk since it sometimes happens that it reduces vision or even leads to its central loss. Only a small percentage of patients can benefit from this procedure because it is used only in the rare cases where the lesion is not located in the center of the macula. Indeed, some lesions are slightly displaced from the center. In cases where the lesions are located exactly in the center of the macula, the laser destroys irreparably and immediately the central vision.
Other treatments are being studied, such as retinal cell transplantation of a healthy area in the affected area.
In addition to being prescribed powerful glasses or magnifying glasses to improve vision, one can make life easier with various adaptation measures, depending on the severity of the disease.
To make reading easier
- Choose large print books . There are also magnifying plastic plates the size of a book page, for example.
- Listen to audio books .
- If you look at sites on the Internet , you can change the screen settings to get the largest characters possible.
- There are also systems of magnifiers to display on the screen an image or document that will be displayed at the desired size.
- It is possible to fix a tiny telescope mounted on one of the lenses of a pair of glasses. Similarly, you can go out with a small pocket telescope to read store signs, street names, etc.
- It is possible to be part of a support group to avoid being isolated because of your visual impairment.
- A psychologist specialized in psychological adjustment to loss of vision can be consulted .
- For the most serious cases, it is possible to follow a training course to learn how to navigate and orient yourself.
- Inform everyone about the vision problem in order to avoid embarrassing situations such as not being able to recognize a cross-acquaintance in the street or difficult to perform certain “easy” tasks, etc.
- Do not drive at night or in bad conditions.
- Request an expertise to “adapt” the housing and make it safe. This includes reducing the risk of falls, for example.