R E V I E W Treatment of neovascular age-related macular degeneration in patients with diabetes Michael Cummings1 José Cunha-Vaz2 1Academic Department of Diabetes and Endocrinology, Queen Alexandra Hospital, Portsmouth, UK; 2Department of Ophthalmology, University Hospital of Coimbra, Centre of Ophthalmology, Institute of Biomedical Research on Light and Image, Faculty of Medicine, University of Coimbra, and Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal Correspondence: José Cunha-Vaz Azinhaga Santa Comba, Celas, 3000-548 Coimbra, Portugal Tel +35 1 239480100 Fax +35 1 239480117 Email cunhavaz@aibili.pt Abstract: The number of patients with type 2 diabetes continues to rise; an anticipated 300 million people will be affected by 2025. The immense social and economic burden of the con- dition is exacerbated by the initial asymptomatic nature of type 2 diabetes, resulting in a high prevalence of micro- and macrovascular complications at presentation. Diabetic retinopathy, one of the potential microvascular complications associated with diabetes, and neovascular age-related macular degeneration (AMD) are the two most frequent retinal degenerative dis- eases, and are responsible for the majority of blindness due to retinal disease. Both conditions predominantly affect the central macula, and are associated with the presence of retinal edema and an aggressive inﬂammatory repair process that accelerates disease progression. The associ- ated retinal edema and the inﬂammatory repair process are directly involved in the breakdown of the blood-retinal barrier (BRB). Yet, the underlying alterations to the BRB caused by the diseases are very different. The coexistence of the two conditions appears to be relatively uncommon, suggesting that diabetes may even protect patients from developing neovascular AMD. However, it is thought that the inﬂammatory repair responses associated with diabetic retinopathy and neovascular AMD may be cumulative and, in patients affected by both, could result in chronic diffuse cystoid edema. Treatment considerations in such patients should, therefore, include the role of retinal edema and the increased susceptibility of patients with diabetes to potential systemic side effects associated with agents administered repeatedly for neovascular AMD treatment. Keywords: diabetes, diabetic retinopathy, neovascular age-related macular degeneration, retina, edema Introduction In 1999, the World Health Organization (WHO) reclassiﬁed the biochemical and etiological deﬁnitions of diabetes mellitus (see Table 1) (WHO 1999). These changes were helpful in better identifying individuals associated with progressively greater risk of developing the pathognomonic microvascular and macrovascular complica- tions associated with diabetes. Diabetes prevalence Type 2 diabetes represents more than 85% of all cases of diabetes. The WHO esti- mated that worldwide, 150 million people over the age of 20 years had the condition in 2000, a number set to rise to 300 million people by 2025 (King et al 1998). The prevalence varies enormously between countries, depending upon numerous genetic and environmental factors. However, the greatest burden appears to be in India, China, the US, Pakistan, Indonesia, the Russian Federation, Mexico, and Brazil, which col- lectively account for more than half of all cases globally (King et al 1998). Expressed as age-speciﬁc prevalence, less than 10% of the European population under 60 years old have type 2 diabetes, yet this increases to 10%–20% in those aged 60–79 years (DECODE 2003). Clinical Ophthalmology 2008:2(2) 369–375 © 2008 Dove Medical Press Limited. All rights reserved 369