Optical Coherence Tomography: Choroidal Imaging

The choroid has an important role in supporting the retinal pigment epithelium and photoreceptor layers and is responsible for maintaining normal retinal function. Pathological changes in the choroid that can be detected by optical coherence tomography (OCT) are observed in diseases such as age-related macular degeneration, pachychoroid disease (e.g., central serous chorioretinopathy, pachychoroid neovasculopathy, and polypoidal choroidal vasculopathy), myopic degeneration, inflammatory disease, inherited retinal and choroidal dystrophies, as well as in choroidal tumors. A quick, noninvasive form of imaging, OCT shows good reproducibility over various platforms and allows consecutive imaging of eyes during the course of follow-up to monitor disease progression and detect recurrence. Advances in OCT imaging combined with the advent of antiangiogenic therapies have revolutionized the treatment of many common retinal diseases. Novel OCT imaging techniques such as enhanced-depth imaging OCT and new technology including swept-source OCT enable enhanced choroidal imaging. These advances can be used to correlate structure with histology, thereby enhancing our understanding of disease pathogenesis. Other developments such as three-dimensional OCT imaging and more reliable tissue segmentation algorithms can produce en face OCT images with automated analysis and quantification of various retinal and choroidal parameters which are useful for both clinical and research applications.