Macular Degeneration - Age-Related Macular Degeneration (AMD)

Age-related macular degeneration (AMD) is an eye disease that can lead to severe visual impairment. The sensory cells in the macula—the central part of the eye—which are specialized for color vision, lose their function. This area of the eye is responsible for sharp vision.

In macular degeneration, this area is severely impaired. The outer edge of the visual field usually remains intact.

Visual Field in Macular Degeneration

It most commonly affects people over the age of sixty. Age-related macular degeneration is the most common cause of severe visual impairment in older adults. It can also lead to blindness.

The reason for this is the declining function of the pigment layer.

Age-related macular degeneration is a chronic disease of the retina in which the pigment epithelium in the macula is primarily damaged. It usually occurs in older adults and can lead to progressive vision loss over time. Both eyes are often affected, although the disease may progress at different rates. Depending on the form of AMD, modern ophthalmology employs various treatment approaches, such as injecting medication into the eye. In addition, a balanced diet rich in vitamins, lutein, and zeaxanthin, as well as their regular intake, is recommended.

The main symptoms are:

• Severe impairment of vision
• A blurred central field of vision or
• A distorted or dark spot

People often first notice the early signs of macular degeneration while reading. The disease occurs in both dry and wet forms.

Age-related macular degeneration is caused by deposits beneath the retina. These whitish or yellowish accumulations are called drusen. They are an early sign of age-related macular degeneration.

As the disease progresses, the layer beneath the retina (the pigment epithelium) thins. The next layer (the choroid) is also affected. Later, the photoreceptor cells die off, which severely impairs vision.

Dry age-related macular degeneration (dry AMD) is the most common form: about eight out of ten cases are of this type. Over a long period of time, the visual impairment is not very pronounced. However, those affected notice that their visual acuity is limited.

Dry age-related macular degeneration may come to a temporary halt or remain stable for an extended period. However, if those affected notice a dark spot, it means that the central field of vision is affected by macular degeneration.

Dry age-related macular degeneration can be divided into three stages:

1. Early stage: The doctor identifies numerous small drusen or a few medium-sized drusen in age-related macular degeneration. Sometimes, those affected notice blurred vision.
2. Intermediate stage: In this stage, the ophthalmologist observes numerous enlarged drusen in the back of the eye. The pigment epithelium becomes thinner due to macular degeneration. Vision is impaired.
3. Advanced stage: In the advanced stage, numerous and larger drusen predominate. The pigment epithelium and retina show thinning, and scar tissue increases. The patient’s vision is already severely impaired.

The wet form is the rarer type of age-related macular degeneration (wet AMD). It develops from dry age-related macular degeneration. This visual impairment occurs in 10 to 15 percent of all cases.

It progresses rapidly, and the loss of central vision occurs earlier than in the dry form. A distinctive feature is that those affected see curved lines rather than straight ones. In advanced AMD, the central visual field appears as a dark spot.

The disease causes edema to form beneath the retina. Because the membrane is ruptured, blood vessels grow from the choroid into the retina.

These blood vessels are also called choroidal neovascularizations. The signaling molecule VEGF (vascular endothelial growth factor) is responsible for the growth of new blood vessels into the retina. However, these vessels are unstable and, when they rupture, cause bleeding that damages the macula.

An ophthalmologist can detect newly formed blood vessels and bleeding in the macula, which are symptoms of macular degeneration.

The basis for the ophthalmologist’s diagnosis is the medical history, during which the ophthalmologist and patient review the patient’s medical history. In general, people aged 60 and older should undergo a preventive screening examination. The ophthalmologist uses various examination methods to diagnose the disease.

To determine visual acuity, the ophthalmologist uses eye charts. The patient reads numbers and digits of varying sizes from the chart.

The phoropter is a special device through which the patient looks while reading. This allows the ophthalmologist to determine both distance and near visual acuity, as well as the necessary corrective lenses.

To detect signs of age-related macular degeneration, the ophthalmologist examines the condition of the eye using a slit lamp. This allows them to examine the structures of the eye, from the eyelids to the cornea and the lens.

Several methods are available for examining the retina:

• Fundus examination

The ophthalmologist examines the retina using fundus examination. This examination allows the doctor to detect changes in the eye, including those affecting the macula.

Diagram of the eye showing the iris, cornea, lens, retina, and its blood vessels, and the macula

• Optical Coherence Tomography (OCT)

Optical coherence tomography (OCT) is the most important procedure in AMD diagnostics. During this procedure, the ophthalmologist measures the thickness of the retina. 

In the dry form of the disease, the retina becomes thinner; in the wet form, it becomes thicker. The examination is painless; patients sit in front of the machine and focus on a bright spot. 

To prepare for the exam, the doctor administers eye drops that dilate the pupil. The doctor then examines the retina to identify changes caused by age-related macular degeneration. These changes may include cysts or fluid in the retina.

• Fluorescein Angiography

Another method for examining the back of the eye is fluorescein angiography. During this procedure, a dye is injected into a vein in the patient’s arm. 

Within just 20 seconds, the blood vessels in the area of the back of the eye become visible. This allows leaky or diseased vessels—such as those seen in wet age-related macular degeneration—to be detected. 

The ophthalmologist takes photographs of the blood vessels and the retina. The patient is given eye drops to dilate the pupil. Their vision may be impaired for up to 12 hours.

• Early Detection: Amsler Grid Test

The Amsler grid test is a useful tool for detecting age-related macular degeneration, and you can perform it at home. This grid-like pattern is also available online.

Amsler Grid Test

Here’s how to perform the Amsler grid test:

1. Test each eye separately. To do this, cover one eye at a time. 
2. Hold the grid about thirty to forty centimeters away from your eye. 
3. Focus one eye on the dark dot in the center. 
4. Now pay attention to the lines. They should be straight.
5. If the lines are blurry, distorted, or broken, or if individual lines are missing, this may indicate macular degeneration. 

The test results differ depending on whether you have the dry or wet form of the condition.

This is what the Amsler grid might look like with macular degeneration

For dry age-related macular degeneration, treatment consists of lifestyle adjustments, as there are no specific, effective treatment methods available. 

Important measures include: 

• A healthy diet rich in vitamins
• Regular exercise
• Dietary supplements to support vitamin intake

For the treatment of the wet form of age-related macular degeneration, therapies are available that can slow or halt the progression of the disease. A complete cure is not yet possible.

• Anti-VEGF Therapy

An effective method for inhibiting new blood vessel growth in wet age-related macular degeneration is anti-VEGF therapy. VEGF inhibitors reduce the growth of unstable blood vessels in the retina and seal off abnormal blood vessels. Since new bleeding and fluid accumulation no longer occur, the edema can “dry up.”

This therapy can slow the progression of age-related macular degeneration, and an improvement in vision is also possible.

The ophthalmologist injects the medication directly into the vitreous humor. This allows the medication to take effect exactly where it is needed. Before the procedure, the doctor administers a local anesthetic to the eye so that the patient feels no pain.

Initially, three injections are administered at monthly intervals. Afterward, the doctor decides how to proceed with the treatment.

• Photodynamic Therapy

In photodynamic therapy (PDT), the patient receives an injection of the active ingredient verteporfin every three to four months. This medication then spreads throughout the bloodstream.

The ophthalmologist irradiates the newly formed blood vessels on the retina with a fine laser beam. This beam strikes the blood vessels filled with verteporfin. 

This contact produces a toxin that leads to the destruction of the abnormal blood vessels. During treatment, the active ingredient must be dosed so that it does not damage the retina. Whether photodynamic therapy is suitable for a patient depends on the type of neovascularization.

• Surgical Removal of Neovascularizations

This surgical procedure is an option for patients with significant bleeding beneath the retina. The surgeon removes the vitreous humor from the eye to suction out the blood from the retina after making an incision. 

In the next step, they replace the vitreous humor that was previously removed with an artificial one made of silicone oil. This procedure carries a risk of additional bleeding during and after surgery. Therefore, doctors carefully weigh the pros and cons before deciding whether to use this method.

To detect age-related macular degeneration early, you should have regular checkups with your ophthalmologist. 

Since the disease initially occurs without symptoms or pain, those affected often do not notice it.

You should have regular glaucoma screenings starting at age 40.

You should begin having screenings for age-related macular degeneration starting at age 60.

You should also avoid smoking. Smoking is a major risk factor for vascular diseases, which can also affect the eyes.

Another key factor is a healthy diet. Fruits and leafy green vegetables should be important components of this diet. The so-called Mediterranean diet is highly recommended. It is based on vegetable oils, plenty of fish, and limited meat consumption.

Magnifying visual aids, such as magnifying glasses or screen readers, can help you make the best possible use of your remaining vision in everyday life.

1. What is age-related macular degeneration (AMD)?
It is a disease of the retina in which the central sensory cells are damaged and sharp vision is lost.

2. What forms of the disease are there?
There are two forms: a dry form and a wet form, with the latter typically progressing more rapidly.

3. What role does the pigment epithelium play?
The pigment epithelium supports the retina’s blood supply—damage to it can lead to degeneration and atrophy.

4. Can the disease be treated?
A complete cure is not possible, but the progression can often be slowed through medication and targeted interventions.