Optical Coherence Tomography (OCT)
Optical coherence tomography (OCT) is noninvasive, noncontact, imaging technique that can make images of structures in the retina with a resolution of 10 to 17 microns. Cross-sectional images of the retina in a fashion similar to ultrasound but at a much higher resolution and using light waves rather than sound waves.
In OCT, the anatomic layers within the retina can be visualized and the thickness of the retina can be measured. This is an exceptional advancement in diagnostic imaging because it allows real-time visualization of the microstructure of a tissue without the need to excise and process a biopsy specimen. It is used both for diagnosis and to guide intervention.
The OCT is useful in visualizing the pathology of many eye diseases including diabetic retinopathy, macular degeneration, macular holes, epiretinal membranes, macular edema, central serous choroidopathy and optic disc pits.
OCT was first introduced in 1991[Huang, 1991] and has since been adapted to a number of clinical biomedical imaging settings including ophthalmology. Its largest ophthalmology impact has been the imaging of the retina.
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Figure 1. Normal OCT
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Figure 2. OCT, Age-related Macular Degeneration
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Figure 3. OCT, Cystoid Macular Edema
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Figure 4. OCT, Diabetic Macular Edema
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Figure 5. OCT, Macular Hole
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Figure 6. Vitreomacular Traction
Above Images by UIHC Diagnostic Imaging Staff
Reference: Huang D, et al. Optical coherence tomography. Science. 1991;254(5035):1178-81.