Age-related macular degeneration

What is age-related macular degeneration (AMD)?

Age-related macular degeneration or AMD is a chronic and degenerative disease of the retina that affects the central area of vision (macula), which makes difficult to read and visualize fine details, such as distinguishing between features of a person’s face, driving, dialing a phone number, or working with a computer.

Who can be affected by AMD?

AMD is one of the main causes of irreversible visual impairment in developed countries worldwide. The risk of suffering AMD varies depending on the ethnicity of the patient; thus, its prevalence is higher in Caucasian patients. Generally speaking, its onset is uncommon in people under 50 years old. AMD prevalence increases with each decade after 50 years and the highest prevalence occurs after 80 years, affecting 20-30% of patients older than 85 years.

Which types of AMD are?

From a clinical perspective, based on the appearance of the macula, AMD patients can be classified into early, intermediate, and advanced AMD.

There are two main types of advanced AMD.

·         Atrophic AMD, also called dry AMD, occurs when the blood vessels under the macula become thin and brittle. Small yellow deposits form, called localized thickenings. Almost all people with AMD start out with the dry form.

·         Neovascular or exudative AMD, also called wet AMD, occurs in only about 10% of people with macular degeneration; however, its clinical presentation is much more aggressive and, therefore, has a greater impact on patients’ quality of life. New abnormal and very fragile vessels grow under the macula. These vessels leak blood and fluid.

Causes of AMD

AMD is a multifactorial disease, which means that multiple factors collaborate in its onset. Risk factors for AMD can be broadly classified into personal or environmental factors. Age is the most important demographic risk factor associated with AMD. Other risk factors related to AMD are: Family history of the disease; high fat diet, poor diets in trace nutrients, female gender, sun exposure, alcohol consumption, and smoking. Among these, smoking has been associated with a substantially higher risk of developing AMD.

Symptoms

It is extremely important to identify the symptoms that can make you suspect AMD. In a person over 55 years of age, with previous good visual acuity, the alarming signs that can lead to suspicion of AMD are:

1.      Visual acuity reduction, both sudden and progressive, that does not improve with the use of corrective lenses.

 

2.      Visual field defect (perceived as a dark spot or very blurred vision) in the central region of vision.

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3.      Different disorders of visual perception, such as:

    1. Image distortion (metamorphopsia): it consists of perceiving straight lines as if they were wavy. Metamorphopsia is a key symptom in the evaluation of a patient with AMD and can be easily recognized using the Amsler grid. It can affect one eye much earlier than the other, so it is very important to scan each eye separately.
    2. Alteration in the size of objects:

                                                              i.      Micropsia: Objects appear much smaller than they really are.

                                                            ii.      Macropsia: Objects appear much larger than they actually are.

4.      Difficulties in daily living activities (for example, watching television, walking down stairs, sewing, working on the computer, recognizing people or turning a corner).

Diagnosis

Although, in general terms, AMD is a bilateral disease (it affects both eyes), its presentation can be asymmetric, that is, it affects first one eye and then the other one. Clinical examination (visual acuity, fundus, Amsler test) is usually sufficient to establish a diagnosis of AMD, although subtle macular abnormalities are best detected with the help of complementary tests such as:

·         Optical coherence tomography (OCT).

·         Fundus autofluorescence.

·         Angiography:

    • Fluorescein
    • Indocyanine green.

Is it possible to prevent AMD onset?

In addition to undergoing periodic ophthalmological examinations from the age of 50, some dietary habits, such as a higher consumption of fruits and the Mediterranean diet, not smoking or wearing sunglasses can prevent the appearance of AMD. In people with a family history of the disease, genetic testing may be recommended.

ADM treatment

Early diagnosis is essential to avoid a great visual loss, since the results of the treatment are better the less advanced the disease is.

Atrophic or dry AMD: Up to now, the treatment of atrophic AMD mainly involves preventive supplementation with a diet rich in vitamins and trace elements and the potential inhibition of disease progression. Supplementation with long-chain omega-3 fatty acids can also help prevent oxidative and inflammatory retinal damage from AMD. Different experimental pharmacological treatments are currently being evaluated for the treatment of this type of AMD.

Exudative, neovascular or wet AMD: At this time, the most effective treatment and the first indication is drug treatment with vascular endothelial growth factor inhibitors, which is one of the most important factors involved in the development of the disease. Treatment is administered by intraocular injections.

In those patients in whom there has been a significant deterioration in visual acuity, the use of visual aids such as magnifying glasses, magnifying glasses, telescopes or good lighting and brightne