Age-related macular degeneration

What it is

Age-related macular degeneration is the most common cause of blindness in the UK. Degeneration of the central retina (macula) is the key feature, and the changes are usually bilateral; the macula is in the center, so the center of the vision is mainly affected. It is a chronic age-related degeneration of the Bruch's membrane, RPE and photoreceptors complex, as a result of which choroidal neovascularization ensues. Traditionally two forms are seen:

• Dry (geographic atrophy): drusen, yellow round spots in Bruch's membrane
• Wet (exudative, neovascular): choroidal neovascularisation, where leakage of serous fluid and blood can result in a rapid loss of vision. It carries the worst prognosis

A more updated classification calls these early age-related macular degeneration (non-exudative, age-related maculopathy: drusen and alterations to the retinal pigment epithelium) and late age-related macular degeneration (neovascularisation, exudative).

Causes and risk

• Age: most patients are over 60 years of age
• Smoking
• Family history
• More common in Caucasians
• High cumulative sunlight exposure
• Female sex