Optical Coherence Tomography (OCT) and OCT Angiography – Recent Advances

Dear Colleagues,

From their use as a research tools to their commercial availability, optical coherence tomography (OCT) and OCT angiography (OCTA) have gained widespread acceptability as imaging modalities in our clinical practice. OCT provides a three-dimensional in vivo histological analysis of the retina with resolution reaching up to 5 µm or lower. OCTA, a non-invasive technique to image the chorioretinal microvasculature, provides three-dimensional details compared to dye-based angiography techniques such as fluorescein or indocyanine angiography. Both spectral and swept-source OCT and OCTA, with wavelengths 840 and 1050 nm, respectively, are commercially available. The inclusion of wide-field imaging techniques has improved our field of view from 20 degrees up to 220 degrees in wide-field OCT (i.e., the retinal periphery), helping diagnose peripheral retinal degeneration, retinoschisis, retinal detachment, and peripheral choroidal pathologies. Different algorithms such as split-spectrum amplitude-decorrelation angiography (SSADA), OCTA Ratio Analysis (OCTARA), and OCT-microangiography complex algorithm (OMAG) are available for OCTA imaging and to provide both qualitative and quantitative information. Further technical improvements in OCTA imaging have increased the scanned area from smaller 3*3 mm slabs to much larger 12*12 mm slabs. These images can be montaged to recreate vascular patterns extending to the equator. Both OCT and OCTA can be useful in assessing retinal vascular diseases, age-related macular degeneration, glaucoma, uveitic pathologies, and ocular tumors. Addressing concerns such as a multitude of artifacts, slower image acquisition speed, lower resolution, the high cost of wide-field OCT machines, and the variability in different OCTA machines related to proprietary algorithms may further enhance the appeal of OCT and OCTA. This Topic summarizes the recent advances in OCT and OCTA and their clinical application in various chorioretinal diseases. We plan to include prospective and retrospective original articles and a few review articles on this Topic.

Dr. Sumit Randhir Singh
Dr. Jay Chhablani
Topic Editors