9.1 Corneal Topography and Tomography
9.2 Confocal Microscopy
9.3 Optical Coherence Tomography - Macula
9.4 Optical Coherence Tomography Angiography (OCT-A)
9.5 Optical Coherence Tomography - Glaucoma
9.6 Optical Coherence Tomography – Anterior Segment
9.7 Fundus Autofluorescence Imaging
9.8 Fundus Angiography - Fluorescein
9.9 Fundus Angiography - Indocyanine Green
9.10 B-scan Ultrasonography & UBM
9.12 Automated Visual Fields
Optical coherence tomography angiography (OCT-A) has emerged as a non-invasive technique for imaging the microvasculature of the retina and the choroid. It utilises laser light reflectance off the surface of moving red blood cells to accurately depict vessels through different segments, thus eliminating the need for intravascular dyes. OCT-A produces images that can be segmented into different levels, e.g.: the superficial retinal plexus, the deep retinal plexus, the outer retina and the choriocapillaris.
The main advantages of OCT-A over conventional fluorescein angiography include its non-invasiveness and the shorter acquisition times. Limitations include artefacts such as projection artefact.
In OCT-A, diseases manifest as the abnormal presence of flow (neovascularisation), anomalous vessel geometry (dilated vessels, aneurysms) or the absence of flow (non-perfusion/capillary dropout). It does not visualise leakage or polyps accurately.
OCT-A is increasingly being utilised to assess retinal and optic nerve disorders.
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