> Macular degeneration

Macular degeneration

Macular degeneration is a disease which affects the macula (part of the retina of the eye), respomsible for central vision.

When the light sensitive cells in the macula, the so-called cone cells, stop functioning, this is called macular degeneration.

Central vision is impaired, while peripheral vision is maintained.

This disease is most common in people 60 years old or older and in this case is called age-related macular degeneration or senile macular degeneration.

Some forms that are rarer are some hereditary types which affect children and young people.

Macular degeneration doesn’t cause blindness. Those affected can see an object or a face, but cannot recognize the detailed feature. Even if some actions such as reading or driving are harder or almost impossible, the preserved peripheral vision helps patients maintain their usual daily routine.

There are two types of common macular degeneration – “dry” (atrophic) and “wet” (exudative). The dry form of macular degeneration is the most frequent type (up to 85 or 90% of all cases). It is connected to aging and thinning of the macular tissues. Loss of eyesight is gradual, and it consists of an inability to tell apart details of a particular object. The “wet” form affects about 10% of all patients with macular degeneration. New blood vessels form in or under the retina with a predisposition to bleeding. Those new blood cells start getting into the retina, harming and destroying the macular cells. The reason for the sudden development of those blood vessels is still unknown. In this shape of the disease, loss of vision is quicker and is larger.

Macular degeneration manifests in a different way.
The condition can be barely noticeable in the early stages. Sometimes it is

only developing in one eye, while the other maintains good vision for years. If it affects the other eye as well, loss of central vision is very noticeable.

Symptoms

The main symptom of macular degeneration is decrease or loss of central vision, while peripheral vision is maintained. Difficulties in detailed and close work such as reading or threading needles. Bent images are seen, straight lines look irrecular, rounded or bent. Objects look different in color, size and shape in each eye. Decreased or blurred vision. In some cases, colors lose their brightness or dark spots appear in the central vision field.

Reasons

The reasons for developing macular degeneration are not known. There are a number of risk factors, which negatively impact protective mechanisms of the eyes and are considered to be part of the causes of macular degeneration.

They include:

– age (main factor) – with aging, the chance of developing macular degeneration increase
– race – it is more common in Caucasians, but can also affect those of other races
– pigmentation – it is more common in people with lighter skin
– color of the iris – similarly to the skin, people with a lighter iris are more predisposed to the condition
– gender – it is more common in women
– untreated high blood pressure
– smoking – a sure risk factor for both types of the disease
– lack of vitamins and minerals
– obesity, metabolite syndrome – connected to a higher risk
– sleep apnea – a risk factor independent from obesity
– direct exposure to sunlight – people who work outside and those on the equator are more predisposed
– high degree of shortsightedness (myopia) – higher risk of macular degeneration or the so-called myopic degeneration

higher levels of cholesterol or blood sugar, which in time can cause degenerative processes

hereditary – frequently macular degeneration can be seen in multiple people in one family. Tests on twins show that genetic factors play a meaningful role. A large number of genes and proteins are connected to the development of the dry and wet forms of macular degeneration.

Diagnostics

What tests are needed to diagnose the disease?

Routine eye exam
Measuring vision sharpness
Tests on the retina

When testing the retina, the ophthalmologist looks for specific signs of macular degeneration. Multiple spots on the macula, known as drusen, are a sign of the dry form of macular degeneration. They are made of lipids and cell leftovers under the pigmented layer of the retina. They look like white or yellow spots that blend together in time. Sometimes they can cause light to medium vision of central vision. Some drusen are a risk factor of progression to wet macular degeneration. Another sign of senile macular degeneration is the thinning of the pigmented layer of the retina and choroid body (the middle layer of the eye).
In the exudative form or macular degeneration, the ophthalmologist can see exudates (fluid), blood, scars and the formed new blood vessels under the retina. Those changes grow quickly, in months to days. In the end, they cause permanent loss of central vision.

When signs of macular degeneration are seen, the doctor assigns more specific tests to the retina such as:

Fluorescent angiography
In it, a fluorescent substance – fluorescein, is injected in the arm, after which a picture of the retina is taken when the substance goes through it. The test shows the localization of blood vessels and signs of vessel anomalies, and the potential for laser treatment.
Indocyanine green angiography
This test uses a different type of contrast substance and allows the doctor to find signs of wet macular degeneration not visible with fluorescein
Optical coherent tomography (OCT)
This is a non-invasive method for visualizing the retina. It is useful when determining the effect of the disease on different layers of the retina, and when checking for signs of swelling and inflammation.
Perimetry
Using it, the localization of lost or decreased retinal function is seen. Patient cooperation is needed.
Test with the Amsler net

Treatment

It is extremely important to consult an ophthalmologist and inform them of all symptoms you have noticed, so that progression of the condition can be limited as much as possible.

Although macular degeneration still cannot be prevented, there are methods that can slow its development and help the patient cope with the gradual loss of vision. In some cases, nutritional supplements and vitamins may slow its progression.
Treatment of the more common “dry” macular degeneration mainly focuses on correcting reduced vision with aids. Specially designed telescopic glasses or television devices can help patients continue many of their favorite activities. In cases of “exudative” (wet) macular degeneration, laser treatment may sometimes be used in the early stages. A precisely focused laser beam is used to burn the leaking blood vessels that damage the macula.
There is considerable debate among doctors about the role of vitamins and minerals in the treatment of age-related macular degeneration. Many believe that a daily dose of antioxidant vitamins—especially zinc, vitamins A, C, and E, selenium, copper, lutein, zeaxanthin, and other antioxidants—may reduce the likelihood of progressive macular degeneration in an eye that is just beginning to be affected. Taking vitamins is recommended for people in the early stages of macular degeneration.

Laser treatment – this may reduce or stop vision loss in the early stages of degeneration. Argon or krypton laser is used to destroy newly formed vessels. Scars remain on the retina, which cause loss of vision in that area, but the spread of degeneration is limited. Unfortunately, laser treatment leads to improvement only in about half of patients, and only a small number meet the criteria for treatment.
Photodynamic therapy – a light-activated substance called verteporfin is injected intravenously, and with the help of a special laser the abnormal blood vessels are closed without injuring the retina. Treatment may take from one to several years. Because the substance is activated by light, exposure to sunlight is contraindicated for about five days.

In advanced stages, Anti-VEGF therapy (injections into the eye) is used to limit the process.

Много важно е да се правят периодични прегледи за проследяване развитието на дегенерацията на макулата и при появата на всяка промяна в зрението да се търси причината. Трябва да се следи и общото състояние – да се контролира кръвното налягане, холестерола, диабета, диетата или всяко отклонение, което повлиява зрението