Age-Related Macular Degeneration is a degenerative disease of the retina and more specifically the macula. The macula is the central part of the retina responsible for sharp, colour vision. In more developed countries, AMD is the leading cause of severe low vision in individuals over the age of 55.
AMD has a unilateral onset and is not certain to affect both eyes
Normal fundus
As mentioned, the macula is responsible for the defined vision of details and enables the appreciation of the slightest nuances of colour. When the macula undergoes degenerative phenomena, however, vision is also severely impaired to the extent that in more advanced cases, a black spot may be perceived in the centre of the visual field, while the peripheral part still allows perception of the surrounding world but in a less precise manner and with less vivid colours.
There are two forms of AMD:
- Atrophic or dry
- Essudative or wet
The two forms share an early stage whose characteristic sign is small yellowish deposits (Drusen) in the macular area. From this stage, the pathology may evolve towards the atrophic or exudative form or not evolve at all.
Atrophic or dry AMD, has a slow course and the late stage is characterised by the death of retinal cells at the macular level due to atrophy (lack of nutrition) resulting in worsening of central vision. Vision loss is usually gradual and depends on the extent of the macular lesions.
Wet exudative AMD, is the most aggressive form of the disease, and can also develop from the atrophic form. In this form, the reduced supply of nourishment and oxygen causes the formation of pathological blood vessels, called neovascular membranes, which penetrate the retina. These neovases have structurally altered walls and are permeable, so that fluid and blood leak out of them, with even severe impairment of central vision.
Symptoms
Symptoms are variable and are related to the progress of the pathology. These mainly consist of:
- Distorted vision, e.g. straight lines of a doorframe appear wavy (metamorphoses)
- Distorted or blurred vision especially in the centre of images
- Altered vision, objects may appear distorted in shape and/or size, colours may appear unclear or inaccurate
- Appearance of a dark or hollow area in the centre of vision (scotoma)
- More light required for reading than in the past tense and individual letters or pieces of words may be missing
Central scotoma
Metamorphoses
Causes
It is difficult to define the triggering causes of AMD, as it is a condition that is considered multifactorial. One could make a long list, certain, in any case, not to be exhaustive.
One can list; however, the risk factors considered the most important to date, distinguishing between modifiable and non-modifiable.
Among the non-modifiable we can report:
- Age – All studies agree that the prevalence, incidence and progression of the disease increase significantly with increasing age.
- Genetics – First-degree relatives of a person with AMD have a 3 times higher risk of developing the same disease than the general population. This indicates that genetic components play an important role in the pathogenesis of AMD.
- Gender – Some scientific studies have shown statistically significant differences in the risk of AMD in the two sexes to the detriment of the female sex, where the disease occurs more frequently.
- Ethnicity -The prevalence of AMD is higher in the white population than in the black population, especially in the wet form.
Modifiable risk factors include:
- Cigarette smoking – this is considered a major risk factor. The incidence of AWD may vary both in relation to the years in which the subject has smoked and in relation to the number of cigarettes smoked. Smoking probably acts by amplifying the risk of AMD by increasing oxidative stress and stimulating the formation of neovases.
- Alcohol – alcohol abuse can lead to an increased risk of AMD even to a considerable extent.
- Diet – an unbalanced diet, rich in animal fats and low in vegetables can lead to an increase in aggression by oxidising substances and a reduction of those substances deputed to counteract their negative action, substances also known as antioxidants, as well as leading to possible weight gain.
- Obesity – obese individuals have shown a higher risk of developing AMD than normal-weight individuals.
- Sedentary lifestyle – a sedentary lifestyle has been correlated with a higher risk of developing AMD.
- Exposure to light – sunlight is considered to be one of the major risk factors for AMD, light has a powerful photo-oxidant activity and directly affects the macula due to its function, so it is necessary to protect oneself during the hours most at risk with good quality sunglasses.
What to do in the event of a diagnosis of AMD?
In the first place, rely on your ophthalmologist of choice who will certainly know how to show you the path to take together to best deal with the condition.
Having regular eye examinations is the most effective way to keep the condition under control. It is fair to know that, paradoxically, the exudative form, which is the most serious, is the one for which there are medical therapies to slow down its evolution, such as intravitreal injections, so regular check-ups are essential in order to be able to implement them in good time.
For his part, the patient can make use of simple systems of self-diagnosis, so that any symptom that suggests a worsening can bring him to the ophthalmologist regardless of the schedule set with him. One example is the Amsler test, which is very useful for following the evolution of maculopathies that have already been diagnosed and is very easy to perform.
The high road is through prevention, which involves the reduction of modifiable risk factors:
- stop smoking,
- reduce alcohol use to a minimum (it should be noted that red wine, in moderate doses, has been shown to be a protective factor),
- implement a diet rich in fruit and vegetables by limiting, for example, the frequent intake of red meat and cold cuts, preferring white meat and fish,
- reduce body weight and engage in appropriate physical activity, which help counteract advancing age,
- use a hat and sunglasses from an early age when doing work or recreational activities in bright sunshine.
Added to this is the importance of using products specifically formulated with antioxidant substances, which are able to exert a protective effect against free radicals and thus help to protect the retina from oxidative and photo-oxidative damage, thus improving its metabolism.