AMD (Age-Related Macular Degeneration)
What is AMD?
AMD (age-related macular degeneration) is a degenerative disease that affects the macula and the central portion of the retina, the part responsible for 90% of vision and where visual acuity is the clearest and most accurate.
It is the leading cause of blindness in those aged over 55 in developed countries and is present to some degree in a third of the population aged over 70. It can present in two forms:
- Dry or atrophic AMD: this is the most common form (approximately 85% of cases) and it progresses slowly and gradually over time. Deposits form (drusen) and changes occur to the pigment epithelium (layer that nourishes and maintains the retina). If it doesn’t receive nutrients, the macula degenerates and can atrophy completely in advanced stages. This type of AMD can evolve to the wet form.
- Wet or exudative AMD: to compensate for the lack of nutrients, sometimes new abnormal blood vessels develop, which can bleed, deform the retina and cause various complications. When this happens, loss of vision is rapid and aggressive, in weeks or a few months.
AMD causes no pain or discomfort aside from the central vision problems. It is a disease that can be very disabling since, although peripheral vision is conserved, the patient has increasing difficulties recognising faces, reading, writing, watching the TV, walking and using the stairs or carrying out various precision tasks.
If you notice a sudden loss of vision, distortion, deformation or alteration in the size of images or the appearance of a fixed black spot in the middle of your field of vision, you must consult your ophthalmologist immediately. You may be developing wet AMD which requires immediate treatment.
The exact causes of AMD are unknown; it is a disease with multifactorial origins with the following clearly demonstrated risk factors:
- Age: AMD usually appears between the ages of 50 and 60 years and its incidence increases with age. In fact, the likelihood of suffering from this increases 4-fold after the age of 75.
- Genetic predisposition: it is estimated that 50% of the risk of suffering from AMD is hereditary and that the likelihood of suffering from it increases between 3- and 6-fold if a first-degree family member is affected. We are currently aware of around twenty genes involved in the pathology and being investigated in this field.
- Smoking: this increases the risk of AMD 6-fold and is the main modifiable factor.
It also influences associated disorders such as obesity, high cholesterol, arterial hypertension, diabetes and cardiovascular diseases. In addition, the development of AMD may be influenced by a lack of antioxidants in the diet, direct and prolonged exposure to the sun or some ocular constraints such as hypermetropia or a history of cataracts surgery.
We can effectively treat wet AMD with the intraocular injection of drugs, which slows the disorder down and allows the majority of patients to maintain and even recover their vision. There is currently no effective treatment for dry AMD although research is ongoing and Miranza clinics are involved in this.
In addition, support from the Low Vision Area, although unable to cure the causes of the disease, may be able to help make the most of the remaining vision.