Describe age-related macular degeneration with its management.

Nature and Risk Factors

• It destroys central vision and spares the periphery, so patients lose the ability to read, recognise faces and drive, while retaining navigational vision. They are never totally blind, and telling them so early is an important part of the consultation
• Risk factors — age, overwhelmingly; smoking, which is the strongest modifiable factor, multiplying the risk two- to four-fold and remaining elevated for years after stopping; genetics, particularly the complement factor H (CFH) and ARMS2/HTRA1 variants, which together account for much of the heritability and place complement dysregulation at the centre of the pathogenesis; family history; hypertension and cardiovascular disease; a diet low in antioxidants and omega-3; obesity; and a light iris

DRY and Wet Disease

• Drusen are the hallmark, and their character matters: hard drusen are small, discrete and yellow, and are a normal ageing change of little significance; soft drusen are larger, pale, with indistinct margins and a tendency to become confluent, and carry a substantially higher risk of progression to both atrophy and neovascularisation. Reticular pseudodrusen are a further high-risk phenotype
• The AREDS and AREDS2 studies established that a supplement of vitamins C and E, zinc and copper, with lutein and zeaxanthin, reduces progression to advanced disease by about a quarter in patients with intermediate AMD or advanced disease in one eye
• Three points about AREDS supplements are examinable: beta-carotene was removed in AREDS2 because it increased lung cancer in smokers and former smokers; the supplement is not indicated in early AMD or in those with no AMD, in whom no benefit was shown; and copper is included to prevent the copper-deficiency anaemia caused by high-dose zinc

Assessment and Support

• The AMSLER grid is the essential self-monitoring tool: a grid of squares viewed at reading distance with reading glasses, one eye at a time, fixating the central dot. New distortion, a missing area or wavy lines means urgent review. Every patient with dry AMD should be given one and taught to use it daily, since conversion to wet AMD is treatable only if caught early
• Optical coherence tomography is the principal investigation, showing intraretinal and subretinal fluid, pigment epithelial detachment and atrophy, and guiding retreatment decisions
• Fluorescein angiography characterises the neovascular membrane as classic (early well-defined lacy hyperfluorescence) or occult; and OCT angiography now demonstrates the membrane without any dye
• Low vision rehabilitation is a treatment, not an afterthought: magnifiers, high-power reading additions, telescopic aids, good task lighting (which is the single most effective and most neglected measure), high-contrast materials, large-print and audio books, screen readers and smartphone magnification
• Eccentric viewing training teaches the patient to use a preferred retinal locus beside the scotoma, and can transform reading ability