Retinal imaging has recently taken a further step forward with the incredible development of a technique capable of providing high-resolution images of the eye’s blood vessels, without any injection of potentially toxic or allergenic compounds: OCT angiography (OCT-A).
OCT-A can map the vascular plexi layer by layer, to precisely show even the smallest vessels and their interconnections and thus identify abnormal vessels or ischaemic areas where blood flow is compromised.
OCT-A has revolutionised care for retinal diseases and now shows similar potential for anterior segment vasculature. However, the quality of the anterior segment scans is still not as good as retinal images.
For example, anterior segment OCT-A does not tolerate the slightest eye movement on the part of the patient because even micro-movements create transverse artifacts on the final images. And so we must wait for technical improvements.
Meanwhile, a new unexpected application is appearing. OCT-A scans are based on moving elements rather than optical densities related to colour or staining with a dye.
The clear discrepancy observed between vascular density under slit-lamp examination and in OCT-A strongly suggests that this new tool not only targets blood vessels, but also a totally nonvisible parallel vascular network: the lymphatic vessels.
We are now viewing structures and tissues we have never seen before or could only access using invasive techniques. A new, truly innovative approach to the anterior segment is now in our hands and will certainly advance with the promising technical progress to come. We just have to wait for the next revolution!