Age-related macular degeneration


AMD is the main cause of visual disability in industrialized countries.

 
 
Early AMD (or “dry AMD”) is the most common subtype, affecting 10% of people aged 65-69, but it is becoming more and more common. Over 25% of people over 80 years of age experience at least some early AMD.

However, dry AMD is mostly mild, having only minor influence on the visual acuity. If the disease progresses, impact on the patient’s everyday life is much more evident.

Advanced AMD may be either “dry” or “wet”, meaning geographic atrophy (central) or exudative AMD, respectively, the latter being more common.

Risk factors for advanced AMD include age, genetics, smoking, heavy alcohol consumption, female gender, cardiovascular diseases, and obesity.
 

 

Symptoms

 
 
 
Early AMD may be asymptomatic but advanced AMD practically always causes visual symptoms. Usually central visual acuity deteriorates and becomes distorted.

Exudative AMD may progress rapidly, within weeks and months. Advanced AMD may cause visual disability, having influence especially on reading, driving, recognizing faces, and on all visual tasks which need good eyesight. However, AMD never causes total blindness, since the surrounding visual field remains undisturbed.
 

 

Causes

 
 
Dry AMD is caused by accumulation of drusen (waste material from retinal cells) material in the pigment epithelium beneath the retina and depigmentation and hyperpigmentation of the pigment epithelium.

Exudative AMD is caused by neovascular change in the foregoing structures, leading to retinal swelling and subretinal fluid, haemorrhages and eventually retinal scarring and loss of central visual functions.

Geographic atrophy is caused by a relatively large local loss of pigment epithelium and visually sensitive cells. The pathophysiology of AMD is being studied closely. It is local metabolic and immunological factors that play a central role here.
 

 

Diagnosis

 
 
Detection of AMD is usually performed by an ophthalmologist, after pupillary dilatation and funduscopy (examination of retina). Classification of AMD and treatment options may require running of fluorescein angiography (FAG) and ocular coherence tomography (OCT).
 

 

Treatment

 
 
There is no cure for AMD. However, progression of the disease may be slowed down, stopped, and sometimes even improved. High doses of certain antioxidants (according to ARED-studies: C- and E-vitamins, copper, zinc and beta-carotene, for non-smokers only) reduce the risk of progression of pre-existing dry AMD.

There is also some evidence that diet containing enough omega-3 and lutein and zeaxanthin carotenoids may indicate lower risk for AMD.

Smoking, heavy alcohol consumption, cardiovascular diseases and obesity expose patients to AMD, appropriate attention on those may reduce risk of dry AMD progression.

However, actual medical treatment does not exist for dry AMD (both early and advanced). If the disease turns into exudative form presenting more severe and rapid visual impairment and subjective impact, there are several alternatives for treatment. Direct laser treatments, photodynamic treatment, and injections into the eye are common possibilities, and their suitability for individual patients depends on several factors, like exact localization of the pathological change and its stage of progression, for instance.


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