AMD is the third most important cause of blindness in the world and the leading cause of blindness in higher income countries with ageing populations.
AMD is a disease affecting the central area of the retina (macula) at the back of the eye. In the early stages of the disease lipid material accumulates in deposits underneath the retinal pigment epithelium. These deposits are known as drusen, and can be seen as pale yellow spots on the retina. The pigment of the retinal pigment epithelium may become disturbed, with areas of hyperpigmentation and hypopigmentation. In the later stages of the disease, the retinal pigment epithelium may atrophy completely. This loss can occur in small focal areas or can be widespread (geographic atrophy). In some cases, new blood vessels grow under the retinal pigment epithelium and occasionally into the subretinal space (exudative or neovascular AMD). Haemorrhage can occur which often results in increased scarring of the retina. The early stages of the disease are in general asymptomatic. In the later stages there may be considerable distortion within the central visual field leading to a complete loss of central visual function.
Approximately 5% of blindness globally is due to AMD(1). It is estimated that globally 196 million (95% credible interval 140—261) people will have AMD in 2020, increasing to 288 million in 2040 (205—399)(2).
The major risk factors for AMD are age, genetic factors and tobacco smoking. Considerable research has focussed on the role of diet, light exposure and association with cardiovascular disease and its risk factors, however, the effects of these risk factors are less certain.
Treatment of AMD has been revolutionised by the use of anti-vascular endothelial growth factor agents that bind to vascular endothelial growth factor or their receptors and slow down the growth of new blood vessels. These interventions are delivered by injection into the eye. However, they are only applicable for the neovascular form of the disease. Currently there is no effective treatment for geographic atrophy. There is some evidence that antioxidant vitamin supplements may slow down the progression of AMD to late stage disease and visual loss.
1. Pascolini D, Mariotti SP. Global estimates of visual impairment: 2010. The British journal of ophthalmology. 2012 May;96(5):614-8. PubMed PMID: 22133988.
2. Wong WL, Su X, Li X, Cheung CMG, Klein R, Cheng C-Y, et al. Global prevalence of age-related macular degeneration and disease burden projection for 2020 and 2040: a systematic review and meta-analysis. The Lancet Global Health. 2014;2(2):e106-e16.
List of Cochrane reviews on AMD
Treatments that are effective
- Antiangiogenic therapy with anti-vascular endothelial growth factor modalities for neovascular age-related macular degeneration
- Photodynamic therapy for neovascular age-related macular degeneration
- Laser photocoagulation for neovascular age-related macular degeneration (effective in slowing down progression of vision loss but no longer in general use)
Treatments that are probably not effective or where effectiveness is currently uncertain
- Antiangiogenic therapy with interferon alfa for neovascular age-related macular degeneration
- Macular translocation for neovascular age-related macular degeneration
- Surgical implantation of steroids with antiangiogenic characteristics for treating neovascular age-related macular degeneration
- Submacular surgery for choroidal neovascularisation secondary to age-related macular degeneration
- Statins for age-related macular degeneration
- Ginkgo biloba extract for age-related macular degeneration
- Laser treatment of drusen to prevent progression to advanced age-related macular degeneration
- Radiotherapy for neovascular age-related macular degeneration
- Complement inhibitors for age-related macular degeneration
- Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration
- Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration
- Omega 3 fatty acids for preventing or slowing the progression of age-related macular degeneration
- Reading aids for adults with low vision
- Surgery for cataracts in people with age-related macular degeneration
Links to key websites
- The Royal College of Ophthalmologists: http://www.rcophth.ac.uk
- NICE website: http://www.nice.org.uk
- National Eye Institute: http://www.nei.nih.gov
- Journal of American Medical Association: http://jama.jamanetwork.com
- AMD Alliance international www.amdalliance.org
- Macular Society www.macularsociety.org
- RNIB www.rnib.org.uk
- Cochrane Eyes and Vision group www.cochraneeyes.org
(IAPB acknowledges Jennifer Evans, Co Coordinating Editor of the Cochrane Eyes and Vision Group and Tanya Moutray, January 2014)