Age-Related Macular Degeneration

Abstract

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, and the prevalence of the disease increases exponentially with every decade after age 50 years. It is a multifactorial disease involving a complex interplay of genetic, environmental, metabolic, and functional factors. Besides smoking, hypertension, obesity, and certain dietary habits, a growing body of evidence indicates that inflammation and the immune system may play a key role in the development of the disease. AMD may progress from the early form to the intermediate form and then to the advanced form, where two subtypes exist: the nonneovascular (dry) type and the neovascular (wet) type. The results from the Age-Related Eye Disease Study have shown that for the nonneovascular type of AMD, supplementation with high-dose antioxidants (vitamin C, vitamin E, and β-carotene) and zinc is recommended for those with the intermediate form of AMD in one or both eyes or with advanced AMD or vision loss due to AMD in one eye. As for the neovascular type of the advanced AMD, the current standard of therapy is intravitreal injections of vascular endothelial growth factor inhibitors. In addition, lifestyle and dietary modifications including improved physical activity, reduced daily sodium intake, and reduced intake of solid fats, added sugars, cholesterol, and refined grain foods are recommended. To date, no study has demonstrated that AMD can be cured or effectively prevented. Clearly, more research is needed to fully understand the pathophysiology as well as to develop prevention and treatment strategies for this devastating disease.

Corticosteroids and Anti-Complement Therapy in Retinal Diseases

“…Unlike neovascular AMD (Cheung and Eaton 2013;Schmidt-Erfurth et al 2014), dry AMD continues to defy searches for a therapeutic target for intervention (Cheung and Eaton 2013). This section of the chapter will review both previous and current therapeutic interventions being tested for dry AMD treatment and the cell signaling pathways targeted by those interventions.…”

“…Smoking also promotes the formation of advanced glycation end-products (AGEs) (Kirkham et al 2003) and deposition of cadmium, which promotes ROS production, in the RPE (Woodell and Rohrer 2014;Kirkham et al 2003). Like smoking, obesity and high-fat diets have also been associated with early AMD and progression to late AMD (Cheung and Eaton 2013). The Beaver Dam Eye Study, for example, suggested a potential link between obesity and AMD (Howard et al 2014).…”

“…Modifiable risk factors for dry AMD include smoking and obesity (Cheung and Eaton 2013). Smoking in particular has been associated with development and progression of AMD (Buschini et al 2015), and some evidence AMD risk has a dose-dependent relationship with smoking (Velilla et al 2013).…”

“…Because observations indicated diets rich in fruits and vegetables may protect against AMD (Ersoy et al 2014;Seddon et al 1994), the Age-Related Eye Disease Study (AREDS) (Age-Related Eye Disease Study Research 2001) was conducted to determine whether a dietary supplement containing high-dose vitamins C and E, beta carotene, and zinc could protect against AMD progression by reducing oxidative stress (Cheung and Eaton 2013). A second study, AREDS2, tested lutein, zeaxanthin, and omega-3 fatty acids for AMD protection (Age-Related Eye Disease Study 2 Research G 2013).…”

Asymmetric dimethylarginine and homocysteine in exudative age-related macular degeneration

“…5 ARMD may progress from the early form to the intermediate form and then to the advanced form, where two subtypes exist: the nonexudative (dry) type and the exudative (wet) type. 3 The nonexudative form is more common and accounts for most ARMD cases. The exudative ARMD (E-ARMD), however, is more debilitating and is responsible for more than 80% of the visual loss in such patients.…”