Age-Related Macular Degeneration
Chapter notes (PDF)PDFAge-related macular degeneration is the leading cause of sight impairment in the UK, classified as dry (90%) or wet (10%), with anti-VEGF injections transforming outcomes for wet AMD.
Key Facts
- AMD is the leading cause of sight impairment in the UK; affects approximately 600,000 people
- Dry AMD (90%): drusen + RPE atrophy → gradual central visual loss; no specific treatment (nutritional supplements may slow progression - AREDS2)
- Wet AMD (10%): choroidal neovascularisation (CNV) → rapid central visual loss; ophthalmic emergency - treat with anti-VEGF injections
- Anti-VEGF agents: ranibizumab (Lucentis), aflibercept (Eylea), brolucizumab (Beovu), faricimab - intravitreal injection; NICE approved (TA155/TA294)
- Symptoms: gradual (dry) or sudden (wet) central visual loss, metamorphopsia (distortion), scotoma
- Amsler grid: detects metamorphopsia; patients with dry AMD should self-monitor for distortion (conversion to wet)
- Risk factors: age >55, smoking (strongest modifiable risk factor), family history, Caucasian, female sex, UV exposure, hypertension
- AREDS2 supplements: vitamins C, E, zinc, copper, lutein, zeaxanthin - reduce risk of progression from intermediate to advanced dry AMD by 25%
Overview
Key Facts
AMD affects central vision while peripheral vision is preserved. Early detection of wet AMD and prompt anti-VEGF treatment are critical for preserving vision.
Epidemiology
- ~600,000 people in the UK; leading cause of certified sight impairment
- Prevalence rises sharply after 55: 10% of 65-74; 30% of >75
- Wet AMD causes 90% of severe visual loss from AMD despite being only 10% of cases
Aetiology
accumulation of drusen (lipid deposits) between RPE and Bruch's membrane
RPE dysfunction
photoreceptor loss
geographic atrophy
breaks in Bruch's membrane
choroidal neovascularisation (CNV) grows into subretinal space
leakage, haemorrhage, scarring
- Risk factors: age, smoking (2-3× risk), family history, APOE/CFH gene variants
Pathophysiology
- Drusen: extracellular deposits between RPE and Bruch's membrane; contain complement proteins, lipids; induce inflammation
- Geographic atrophy (dry): progressive loss of RPE and photoreceptors; central scotoma develops
VEGF-driven angiogenesis
leaky immature vessels
subretinal/intraretinal fluid
macular oedema
haemorrhage
scarring (disciform scar)
rapid irreversible central vision loss
Clinical Presentation
Dry AMD
- Gradual central visual loss (months to years)
- Difficulty reading (small print, newspaper)
- Difficulty recognising faces
- Need for brighter lighting
- Drusen and RPE changes on fundoscopy
Wet AMD
- Rapid central visual loss (days to weeks)
- Metamorphopsia (straight lines appear wavy - Amsler grid positive)
- Central scotoma
- Fundoscopy: subretinal/intraretinal fluid, haemorrhage, grey-green CNV membrane
Red Flags
Sudden metamorphopsia or acute central visual loss in patient with known dry AMD
wet conversion
urgent ophthalmology referral (within 2 weeks; treatment should start within 14 days)
- Dense central scotoma affecting both eyes → CVI registration, low vision services
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Diabetic maculopathy | Diabetic, microaneurysms, hard exudates | OCT, FFA |
| Central serous chorioretinopathy | Younger, unilateral, serous detachment | OCT, FFA |
| Macular hole | Sudden central scotoma, positive Watzke-Allen | OCT |
| Epiretinal membrane | Metamorphopsia, mild visual loss | OCT |
| Myopic macular degeneration | High myopia, lacquer cracks, CNV | OCT, FFA |
Diagnosis / Investigation
Bedside
- Visual acuity (Snellen)
- Amsler grid: metamorphopsia detection (distortion of grid lines)
- Fundoscopy (dilated): drusen, RPE changes, haemorrhage, CNV, atrophy
Bloods
- Not routinely needed
Imaging
- OCT (optical coherence tomography): gold standard for diagnosis and monitoring
- Drusen, RPE atrophy, intraretinal/subretinal fluid, CNV
- Fundus fluorescein angiography (FFA): identifies CNV type and location
- OCT angiography (OCTA): non-invasive vascular imaging; detects CNV without dye injection
- Fundus autofluorescence (FAF): maps geographic atrophy
Special Tests
- Serial Amsler grid monitoring (dry AMD patients)
- Home monitoring devices (ForeseeHome) in high-risk patients
Management
Non-pharmacological
- Smoking cessation (most important modifiable risk factor)
- Low vision aids: magnifiers, large print, electronic aids, lighting
- CVI registration: when eligible; access to social support
- Amsler grid self-monitoring: for dry AMD patients to detect wet conversion early
- Driving: inform DVLA if visual standards not met
Pharmacological
- Wet AMD - anti-VEGF intravitreal injections (NICE TA155, TA294, TA486):
- Aflibercept (Eylea) 2mg: loading 3 monthly injections then treat and extend (8-16 weekly)
- Ranibizumab (Lucentis) 0.5mg: monthly or PRN
- Faricimab (Vabysmo): bispecific (anti-VEGF + anti-Ang2); longer intervals
- Brolucizumab: potent but risk of intraocular inflammation
- Treatment started within 14 days of diagnosis (NICE target)
- Dry AMD:
- No specific treatment for early dry AMD
- AREDS2 supplements: for intermediate AMD (vitamins C, E, zinc, copper, lutein, zeaxanthin) - reduce progression risk by 25%
- Pegcetacoplan (C3 complement inhibitor): FDA-approved for geographic atrophy (emerging; not yet NICE-approved in UK at time of writing)
Surgical/Interventional
- Photodynamic therapy (PDT): verteporfin + laser; now rarely used (superseded by anti-VEGF)
- Submacular surgery: rarely performed; for large submacular haemorrhage (pneumatic displacement + anti-VEGF)
Referral Criteria
- Suspected wet AMD: urgent ophthalmology referral (aim treatment within 14 days)
- Dry AMD with drusen: optometrist monitoring; annual review
- CVI: when eligible for registration
Prognosis
- Dry AMD: slow progression over years; geographic atrophy causes gradual central vision loss; peripheral vision preserved
- Wet AMD (treated): anti-VEGF stabilises or improves vision in ~90%; mean gain of 8-15 letters (ANCHOR/MARINA/VIEW trials)
- Wet AMD (untreated): rapid loss of central vision over weeks-months
- Anti-VEGF treatment is ongoing (often for years); treatment burden is significant
- AREDS2 supplements: reduce progression from intermediate to advanced AMD by 25%
- Vision loss significantly impacts quality of life, independence, and mental health
Other Relevant Information
Classification of AMD
| Stage | Features | Management |
|---|---|---|
| Early dry | Small/medium drusen, no RPE changes | Observation, lifestyle |
| Intermediate dry | Large drusen ± RPE changes | AREDS2 supplements, monitoring |
| Advanced dry (geographic atrophy) | RPE and photoreceptor loss | Low vision support |
| Wet (neovascular) | CNV, fluid, haemorrhage | Anti-VEGF injections |
Key Anti-VEGF Trials
| Trial | Finding |
|---|---|
| ANCHOR/MARINA | Ranibizumab prevents visual loss and improves vision in wet AMD |
| VIEW 1/2 | Aflibercept non-inferior to ranibizumab; less frequent dosing |
| AREDS/AREDS2 | Supplements reduce progression of intermediate dry AMD by 25% |