Investigations
1st investigations to order
Amsler grid
Test
Useful for determining subjective changes in central (macular) visual field.
Distortion (metamorphopsia) may represent active areas of macular exudation.[50]
Dark areas (scotomas) may represent atrophic areas of the macula.
Result
central area of distortion or scotoma
optical coherence tomography
Test
Recommended if clinical examination shows signs of macular neovascularisation (MNV) and leakage.
Definitive test for confirming the presence of retinal pigment epithelial changes, subretinal and intraretinal fluid.[4]
Used to monitor changes in the volume of intraretinal and subretinal fluid during treatment for MNV.[43]
Can be used to confirm the presence of a hyper-reflective (fibrovascular) scar.
Result
intraretinal fluid; subretinal fluid; pigment epithelial detachment; loss of normal retinal pigment epithelium and photoreceptor architecture; subretinal hyper-reflective material, hyper-reflective scar; decreased choroidal thickness
Investigations to consider
fluorescein angiography
Test
May be ordered if history and/or clinical examination or optical coherence tomography suggests macular neovascularisation (MNV), and is considered the definitive test for the confirmation of MNV and active leakage.[4][41]
May be used to assess the location of the MNV in relation to the centre of the fovea.
Can be used to confirm the presence of drusen (autofluorescence), geographic atrophy (transmission defects), and MNV (expanding hyperfluorescence).
Can be used to distinguish between types of MNV.
Result
transmission defects; areas of expanding hyperfluorescence; focal areas of staining
indocyanine green angiography
Test
Allows a better visualisation of the deeper choroidal vessels. It may be helpful in situations where the source of leakage is obscured by a haemorrhage of the retina, which makes interpretation of fluorescein studies difficult.
It can also be helpful to identify features of idiopathic polypoidal choroidal vasculopathy and in identifying type 3 MNV.[42][46]
Result
hyperfluorescence; may show areas of dye leakage
autofluorescence imaging
Test
Useful for delineating areas of geographic atrophy in dry age-related macular degeneration.[41] Can also be used to detect drusen and subretinal drusenoid deposits and to confirm lipofuscin deposition.
Increased autofluorescence bordering geographic atrophy can indicate higher risk of progression.
Result
areas of hypo-autofluorescence/absence of autofluorescence delineate areas of geographic atrophy; subretinal drusenoid deposits appear as spots of reduced autofluorescence; brighter areas represent accumulation of lipofuscin
Emerging tests
genotyping
Test
Useful only for research purposes.
May be helpful in prognostic identification.
Result
genetic factors that predispose to age-related macular degeneration
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