R E V I E W Age-related macular degeneration and the aging eye Rita Ehrlich1 Alon Harris1 Nisha S Kheradiya1 Diana M Winston1 Thomas A Ciulla3 Barbara Wirostko2 1Indiana University School of Medicine, Department of Ophthalmology, Indianapolis, IN, USA; 2Stony Brook University Medical Center Research Way, Department of Ophthalmology, Stony Brook, NY, USA; 3Retina Service, Midwest Eye Institute, Attending Physician and Surgeon, Methodist Hospital, Indianapolis, IN, USA Correspondence: Alon Harris Department of Ophthalmology, Indiana University School of Medicine, 702 Rotary Circle, Indianapolis, IN 46202, USA Tel +1 317 278 0177 Fax +1 317 278 1007 Email alharris@indiana.edu Abstract: Age-related macular degeneration (AMD) is an ocular disease that causes damage to the retinal macula, mostly in the elderly. Normal aging processes can lead to structural and blood ﬂow changes that can predispose patients to AMD, although advanced age does not inevitably cause AMD. In this review, we describe changes that occur in the macular structure, such as the retinal pigment epithelium and Bruch’s membrane, with advancing age and in AMD. The role of genetics in AMD and age-related changes in ocular blood ﬂow that may play a role in the pathogenesis of AMD are also discussed. Understanding the pathophysiology of AMD development can help guide future research to further comprehend this disease and to develop better treatments to prevent its irreversible central vision loss in the elderly. Keywords: age-related macular degeneration, aging, blood ﬂow, eye, retina, macula, vision Introduction Age-related macular degeneration (AMD) is an ocular disease that involves the posterior aspect of the retina called the macula. The macula facilitates central vision and permits high-resolution visual acuity due to its dense concentration of cone photoreceptors (Fine et al 2000). There is an early and late stage of AMD. In the early stage, there is formation of large drusen and pigmentary abnormalities (Fine et al 2000). The late stage is divided into two groups: nonexudative or “dry” form and an exudative/neovascular or “wet” form. The nonexudative form is characterized by atrophic changes in the macula and clinically, has a slower deterioration and better preservation of visual acuity than exudative AMD (Fine et al 2000). Exudative AMD involves choroidal neovascularization, which is the formation of new abnormal blood vessels in the choriocapillaries through Bruch’s membrane (Figure 1). These vessels have a greater tendency of leakage and bleeding into the macula, ultimately leading to irreversible damage to the photoreceptors if left untreated (Fine et al 2000). Hence, the exudative form accounts for most cases of signiﬁcant visual loss from AMD (Ciulla et al 2001). AMD is the leading cause of visual deterioration and legal blindness in patients over 60 years of age (Klein et al 1997). The loss of central vision and high-resolu- tion visual acuity from untreated AMD can lead to an irreversible loss of reading, facial recognition, and driving (Fine et al 2000). Changes in the macula occur over time and occur more often in the elderly. The prevalence of AMD among 40- to 49-year-olds is 2.1%, which increases dramatically to 35% among those over 80 years of age (National Eye Institute 2007). Additionally, the disease can progress with approximately 10%–20% of patients with nonexudative AMD progressing to the exudative form if untreated (Hyman and Neborsky 2002). Furthermore, almost 40% of patients have bilateral disease (Topouzis et al 2006). The risk factors for AMD include ethnicity, gender, hypertension, genetics, diet, and sunlight exposure. Studies Clinical Interventions in Aging 2008:3(3) 473–482 © 2008 Ehrlich et al, publisher and licensee Dove Medical Press Ltd.This is an Open Access article which permits unrestricted noncommercial use, provided the original work is properly cited. 473