New Swept-Source OCT for Glaucoma: Improvements and Advantages

When we refer to sweptsource optical coherence tomography (SS-OCT), “swept source” refers to the type of laser incorporated into the device. Instead of the superluminescent diode laser typical of conventional spectral domain OCT (SD-OCT), SS-OCT uses a short-cavity swept laser. Although the swept-source laser has a wavelength centered at approximately 1 μm, the laser actually changes, because it sweeps across a narrow band of wavelengths with each scan. Like SD-OCT, SS-OCT has a fi xed reference arm, but it does not use a spectrometer. Instead, a complementary metal oxide semiconductor camera is employed, along with two fast parallel photodiode detectors. The result is that SSOCT is able to achieve the highest imaging speed of any commercially available OCT with 100,000 A-scans obtained per second. Additionally, SS-OCT has a high axial resolution of just 5 μm and an improved signal-to-noise ratio. With a basic understanding of the technical differences between conventional and SS-OCT we can now explore the advantages of this new technology.