Age-Related Macular Degeneration and Its Association With Neurodegenerative Disorders

Abstract

Age-related macular degeneration (AMD) is a highly prevalent macular condition that primarily affects the older population. It is the primary cause of blindness amongst the elderly population. It is an inflammatory disease that characteristically shows choroidal neovascularization and geographic atrophy. The exact pathomechanism of developing AMD is not known. However, certain factors such as increased age, smoking, genetic factors and certain environmental factors are usually associated with the development of the disease. AMD also involves oxidative stress-mediated destruction of retinal pigment epithelial cells and, consequently, that of retinal photoreceptors. Alzheimer's disease (AD) is a degenerative disorder involving the nervous system that usually affects people aged 65 and over. Both AMD and AD are age-related, degenerative conditions that have several similarities and share many of the same risk factors such as vascular conditions like arteriosclerosis, high blood pressure and obesity. It is believed that the early emergence of the clinical manifestations of AMD and AD may also be significantly influenced by oxidative stress and genetic polymorphism in complement factor H. A common pathogenic pathway between AD and AMD is quite likely. Amyloid-β is an aberrant protein that accumulates within the brains of Alzheimer's patients and appears as plaques on magnetic resonance imaging (MRI). These plaques are a pathognomonic sign of Alzheimer's disease. Similar to this, amyloid-β deposits are reported to build up beneath the retina of AMD patients, which appear as tiny clusters of protein-lipid substances known as drusen. It has also been found that individuals suffering from AMD exhibit an increased chance of developing AD than those with no AMD.

Comparative Analysis of Retinal Structural and Angiographic Parameters in Diabetic Patients, Alzheimer’s Disease Patients, and Healthy Controls: An OCT-Based Study

“…Oxidative stress boosts BACE1 protein levels through the PKR-eIF2α pathway, contributing to Aβ production. The association of Drusen and AMD with AD indicates a possible link between retinal changes and neurodegenerative processes [ 15 , 16 ]. Shared characteristics between AMD and AD, such as aging association, unknown etiology, and senile plaques in both the retina and cerebral grey matter, underscore parallel pathogenesis.…”

Age-Related Macular Degeneration: An Exponentially Emerging Imminent Threat of Visual Impairment and Irreversible Blindness

“…In AD, hallmark features are the accumulation of hyperphosphorylated tau (p-tau) and amyloid-beta (A-beta) proteins in the extracellular space, leading to neuroinflammation, brain iron dyshomeostasis, and delayed neuronal death. These overlapping pathological mechanisms between AMD and AD contribute to their similarity [ 48 ].…”

Familial Dominant Drusen: Novel Data on Pathogenesis (Literature Review and Clinical Case Presentation)

“…Кроме того, следует иметь в виду, что при ВМД могут иметь место схожие с сотовидной дистрофией механизмы друзообразования. Ведь известно, что ВМД, согласно современным представлениям, относится к нейродегенеративным заболеваниям глаз с относительно частой ассоциацией с другими нейродегенеративными заболеваниями [45][46][47]; в развитии патологических изменений на глазном дне при ВМД имеет место заинтересованность нервных волокон хориоидальных сосудов и клеточных элементов сетчатки и хориоидеи нейрального происхождения [48][49][50][51]; были получены положительные результаты нейропротекторной терапии при ВМД [52,53].…”