AMD: understanding age-related vision loss

AMD is a degenerative disease that affects the central area of the retina, which is the macula. This degeneration causes a progressive deterioration of the cells and pigment epithelium of the retina, resulting in a loss of central vision. There are two types of AMD:

– Dry or atrophic AMD, affects 50-80% of patients and is characterized by a slow and progressive progression. The deposits that accumulate in the area atrophy the macula and cause the patient to slowly lose vision in the central part of his or her visual field.

– Wet or neovascular AMD, characterized by the growth of new blood vessels with altered permeability walls, eventually leads to fluid and blood leakage in the macula. The loss of vision in this variant is more abrupt and accentuated.

Causes of AMD

AMD is caused by the aging of the central retinal area, so the main risk factors are age and genetic predisposition. In addition, smoking and hypertension may increase its occurrence.

Contrary to what many patients believe, it is not related to any specific activity such as reading, sewing or driving at night.

Symptoms of AMD

Patients progressively lose central vision, resulting in difficulties in reading, writing, driving, sewing or performing other precision tasks. The disease is usually asymmetrical, although bilateral involvement occurs during the course of the disease. When the loss of visual acuity is sudden and severe, the patient notices it immediately and should go to the emergency department. However, sometimes the loss of visual acuity is gradual, and for this reason, the patient is not aware of the visual problem.

A very simple test that can be performed on patients with AMD is to perform the Amsler grid once a week, which consists of first covering one eye and then the other eye while looking at the grid. If the lines are twisted, it is highly recommended to see a specialist in Ophthalmology.

Treatment of wet AMD or neovascular AMD

In recent years, with the introduction of intravitreal antiangiogenic injections, the management and prognosis of this disease has changed completely. This treatment is used to slow the progression of wet AMD, the function of these antiangiogenic drugs being to stop the growth of abnormal blood vessels. A decade ago, these patients were irremediably evolving towards blindness, and today, the loss of visual acuity is much more controlled.

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During the first year, an average of 6 – 9 injections are usually performed, decreasing to 4 – 6 in the second year. The injections are performed in a sterile room or operating room under topical anesthesia. The procedure is quick and the associated risks (bleeding, severe intraocular infections, retinal detachment, etc.) are generally low. This injection treatment is maintained as long as there is neovascular disease activity. Once the neovascularization becomes inactive or when macular scarring occurs, close monitoring is recommended, but further treatment is no longer necessary or beneficial.

There are numerous studies currently underway in neovascular AMD that are analyzing new drugs with the aim of obtaining greater efficacy against the neovascular activity of the disease and with a longer duration of action, which would result in the need for fewer intravitreal injections to control the disease.

Treatment of dry AMD

There is no effective treatment for this pathology, although the administration of nutritional antioxidant complexes such as multivitamins in capsules slows down the evolution of the disease.

Regardless of the type of AMD, it is advisable to advise patients who request it to go to opticians specialized in low vision, because although this depends on retinal health, there are different optical aids that can partially alleviate the visual deficit and make it easier for them to carry out daily activities.

Currently, the main lines of research are focused on genetic studies to determine which patients are predisposed to suffer AMD, with the aim of detecting, in the near future, those people with a higher risk of suffering from the disease and to carry out an exhaustive follow-up of them.