High-resolution visible light OCT of the human retina with combined superluminescent diodes.

Abstract

High-resolution optical coherence tomography (OCT) requires broadband, spatially coherent light sources. Today, the source of choice for visible light OCT, the supercontinuum (SC), is bulky, expensive, and prone to excess noise. Here we demonstrate high-resolution visible light OCT of the human retina with a combined superluminescent diode (SLD) source. The source is longer in wavelength than the high blue light hazard range but shorter in wavelength than the high photopic efficiency range, ensuring subject safety and comfort. We report an axial resolution of 3.2 µm in the retina. We find that Bruch's membrane is well-delineated in subjects without ocular pathology, even though the axial resolution is ∼3× coarser than SC visible light OCT. Imaging of intermediate age-related macular degeneration is also shown. Within the cyan-green wavelength range of the SLD, optical density spectra resemble those of macular pigments. While the combined SLD approach does not achieve the micrometer-scale resolution of the SC, it potentially reduces the cost and complexity of visible light OCT while providing novel disease-relevant biomarkers, to the best of our knowledge, in human retina.