New Technology for Ultrahigh Resolution Optical Coherence Tomography Imaging Using Diode Light Sources

Abstract

Abstract: : Purpose: To demonstrate new technology for ultrahigh resolution optical coherence tomography (UHR–OCT) imaging using low–cost, commercially available, superluminescent diode light sources. To demonstrate imaging in the clinical setting and to compare with UHR–OCT using femtosecond lasers and standard resolution OCT. Methods: An UHR–OCT system has been developed which enables ultrahigh resolution imaging in the ophthalmic clinic using a new, low–cost, commercially available, turnkey, diode light source. This diode light source achieves ultrahigh resolutions without the need for femtosecond lasers which are typically required for UHR–OCT. The light source has a bandwidth of 155 nm with the central wavelength at 890 nm. UHR–OCT using this source achieves axial image resolutions of better than 4 um and image sizes of 3000 axial pixels by 600 transverse pixels. Comparative studies are performed using a femtosecond laser light source with better than 3 um axial resolution and a standard resolution commercial StratusOCT instrument with ∼10 um axial resolution. Imaging was performed in both normal subjects and patients with retinal diseases. Results: The ultrahigh resolution OCT images achieved with the diode light source are comparable to the images achieved with the femtosecond laser light source and significantly better than the images achieved by the standard resolution StratusOCT. Compared to standard resolution OCT, the improved axial resolution of the UHR–OCT images with the diode light source enables better visualization of intraretinal architectural morphology such as the nerve fiber layer, ganglion cell layers, and photoreceptor layers. Conclusions: UHR–OCT imaging that is comparable to current state–of–the–art resolution can be performed using a superluminescent diode light source. To date, UHR–OCT imaging has only been achieved with expensive femtosecond laser light sources, preventing the widespread application of the UHR–OCT technology. The ability to perform UHR–OCT imaging using a low–cost, commercially available, turnkey diode light source may enable future widespread use of ultrahigh resolution OCT technology.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: non–clinical • retina