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Age-Related Macular Degeneration, Genetic Testing

Age-related macular degeneration (AMD) is a progressive eye condition that mainly affects the elderly, creating degeneration of the central part of the retina called the macula. This leads to loss of central vision, affecting activities such as reading and recognizing faces. Age-related macular degeneration can be classified as dry or wet, which involves abnormal blood vessel growth. Although there is no cure, some treatments, such as anti-VEGF, can help manage symptoms and slow the progression of the disease. The assessment of the Polygenic Risk Score for age-related macular degeneration is based on examining 9 gene polymorphisms.

Genetic testing for age-related macular degeneration is included along with 12 other diseases in the Genetic Screening for Sensory Organs and Skin Diseases, Polygenic Risk Score.

Causes and non-genetic risk factors

There are two primary types of age-related macular degeneration: dry and wet. In the former (80% of cases), yellow deposits, called Drusen, form, which, when small, need not impair vision, but as they increase in size and number, they can obscure or distort your vision, and as it worsens, it can lead to loss of central vision. In the wet form (10% of AMD), blood vessels grow under the macula, leak blood, and fluid into the retina, and can distort vision and cause scarring, leading to permanent loss of central vision.

The exact causes that trigger this ocular degeneration are unknown, but in addition to genetic support, the following risk factors may also contribute to its development:

  • Age above 50 years, and in 2/3 of the cases, it will be women versus 1/3 of males. Similarly, Caucasian ethnicity is the highest risk, followed by Chinese, Hispanic/Latino, and lastly African American
  • Smoking. It has probably been related to the decrease in the amount of oxygen associated with smoking, including the ocular system
  • Elevated blood pressure. Probably also related to the oxygen restriction to the ocular system associated with this condition
  • Having heart disease such as angina, stroke, myocardial infarction
  • Obesity, high cholesterol levels, and diets rich in saturated fats (present in foods such as meat, butter, and cheese), as well as alcohol intake, would increase the risk of developing age-related macular degeneration
  • Prolonged sun exposure due to the effect of the sun's ultraviolet rays

Symptomatology varies widely among those affected, although it most commonly appears after age 55. In addition, there are usually no symptoms in the early stages of AMD. The most common sign, and one of the first to appear, is the presence of drusen, yellowish deposits in the retina, which an ophthalmologist easily identifies. As the pathology progresses, the following symptoms may also appear:

  • Blurred or fuzzy vision, difficulty recognizing familiar faces
  • Distortion of straight lines, a dark and empty area, or a blind spot appears in the center of vision
  • Loss of central vision, necessary for daily tasks and functions

There is no preventive treatment as such, but there are recommendations that can delay the development of the disease or slow its progression:

  • Follow a healthy diet, including dark green leafy vegetables (such as spinach) and fish, which are sources of omega-3 fatty acids, antioxidant vitamins A, C, and E, lutein and zeaxanthin, and minerals such as copper, zinc, magnesium, and manganese. Limit the intake of saturated fats. The use of supplements with antioxidant vitamins and zinc can contribute to reducing this risk
  • Stop smoking and avoid alcohol intake
  • Protect your eyes with sunglasses to block the harmful effects of ultraviolet (UV) rays

After 60, it is essential to visit the ophthalmologist regularly, especially if there is a family history of the disease. Vision tests are necessary in the elderly. Vision in both eyes should be checked periodically, with tests as simple as covering one eye and then the other and checking the differences when looking at a distant object or checking with an Amsler grid.

Preventing the progression of maculopathy to age-related macular degeneration consists of taking measures to avoid choroidal neovascularization (the growth of new blood vessels in the center of the macula). The only effective preventive measure is smoking cessation, as the use of antioxidants such as beta-carotene, vitamin C, tocopherol, or zinc has not been shown to have a preventive effect. Once maculopathy is established, the efficacy of antioxidant zinc supplementation has not been demonstrated. It has been clinically observed that laser photocoagulation of drusen (yellow deposits under the retina) leads to their disappearance, and the retina regains an almost normal appearance. Unfortunately, despite several clinical studies that vary the protocol slightly, the disappearance of drusen does not reduce the risk of developing choroidal neovascularization.

Additional information
Results Time4 - 5 Weeks
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