Age-related Macular Degeneration
Reference: Ape RS 2021 in NEJM
AMD appears to affect men and women similarly
AMD severity has been associated with
increasing age
uncontrolled hypertension
smoking
overweight
There is also a strong genetic predisposition
Age related eye disease studies (AERDS and AERDS2)
advanced amd is classified as
neovascular AMD
atrophic AMD
neovascular AMD is characterised by neovascular proliferation underneath the neuroretina. This is also called choroidal neovascularisation.
atrophic AMD is characterised by atrophy of the RPE and overlying neurosensory retina. This is also called geographic atrophy
choroidal neovascularisation and geographic atrophy may develop in the same eye, because they are on the same continuum of disease activity
In addition to choroidal neovascularisation, there are two other forms of AMD-associated neovascularisation - polypoidal choroidal vasculopathy - retinal angiomatous proliferation
neovascular amd is responsible for the majority of severe vision loss
historically, angiography with fluorescein or indocyanine was used to assess the choroidal or retinal vasculature
Indocyanine was particularly useful for identifying the choroidal vasculature for polypoidal choroidal vasculopathy or retinal angiomatous proliferation
This has now largely been replaced by optical coherence tomography
fundus autofluorescence is useful to assess the health of the retinal pigment epithelium
the age related eye disease studies showed that oral supplementation may be helpful in preventing progression from intermediate to advanced disease
the supplementation included:
Vitamin C 500 mg
Zinc 80 mg with Copper 2 mg (added to avoid zinc-related copper deficiency)
Vitamin E 400 IU
Beta carotene 15 mg
However, beta carotene has been associated with an increased risk of lung cancer amongst current or past smokers
In the age related eye disease study 2, beta carotene was replaced with
Lutein 10 mg
Zeaxanthin 2 mg
Other modifiable risk factors include:
losing weight
stopping smoking
good blood pressure control
The fluid in macular degeneration can be due to leaky blood vessels or haemorrhage
identifying polypoidal choroidal vasculopathy is important because when present, treatment with photodynamic therapy may be beneficial
This involves an intravenous injection of verteporfin, a compound which can be photoactivated and selectively binds to abnormal blood vessels. Verteporfin is then activated with a lower power laser to induce vascular regression
a combination of photodynamic therapy and anti-VEG thearpy results in greater gain in visual acuity in polypoidal choroidal vasculopathy. This benefit has been observed when photodynamic therapy is used in conjunction to ranibizumab but not with aflibercept