Optical Coherence Tomography (OCT) is a noninvasive and quick cross-sectional imaging technique that uses low-coherence interferometry, which is similar to ultrasound imaging except that it uses light instead of sound, to obtain images of the retina. The OCT functions as a type of optical biopsy to produce either a single line two dimensional image of the 10 layers of the retina and part of the choroid, or a multiple line three dimensional image of the macula to assess anatomical changes or of the optic nerve head to determine if there is swelling. This high resolution reconstruction of retinal anatomy takes minimal time to acquire and can be reviewed within minutes. The Spectralis OCT contains a TruTrack active eye tracker which reduces noise to improve the image quality and also allows for AutoRescan, which automatically places follow up scans directly in the same location as the original image, improving our ability to track changes within a patient’s retina and bypassing operator variability.
Axonal and neuronal degeneration are commonly associated with a variety of disabilities in many neurological disorders. Within the central nervous system, the retina is unique in that it contains axons and glia, but no myelin and therefore holds the potential to give insight into the effects of neurodegenereation, neuroprotection and possibly neurorestoration. Having this quick processing tool holds the potential for increasing our comprehension of neurodegeneration and its association with specific disabilities in neurological diseases.
The green line is a single line B scan, circling the optic nerve. This 3.4 mm circle has been proven to be the most reproducible for measurement of the RNFL thickness.