Low and Loss of Vision in the Elderly

Abstract

Age-related changes occur in all structures of the eye causing varied effects. With ageing, lens opacities and changes in the vitreous occur and the vitreous gel undergoes liquefaction. A number of changes occur in the retina including accumulation of lipofuscin, thickening of Bruch’s membrane, narrowing of the choroidal arteries and accumulation of material forming soft drusen. The four main causes of low or loss of vision are age-related macular degeneration (AMD), glaucoma, cataract and diabetic retinopathy. The pathophysiology of AMD is complex and unclear, and the pathological processes implicated are accumulation of lipofuscin, formation of drusen, neovascularisation and inflammation. Complement system plays a vital role in the pathology of AMD. In glaucoma, elevated intraocular pressure and vascular dysfunction are said to contribute to initial insult and the ultimate result is death of the retinal ganglion cells causing irreversible visual loss. Cataract of old age is multifactorial with genetic, environmental and biochemical factors which act synergistically. A number of biochemical pathways have been proposed as possible links between hyperglycaemia and diabetic retinopathy (DR). The instrumental pathways include increased polyol pathway, activation of protein kinase C and increase exposure of growth factors such as vascular endothelial growth factor (VEGF).