Fig. 4: Visible light OCT visualizes a new outer retinal band with an improved spectrometer.

a Cross-sectional linear-scaled image of a pigmented mouse retina, acquired by a visible light OCT system with a spectrometer aligned using excess noise correlations (Figs. 2 and 3). A total of 1024 frames, acquired over 17.5 s with a 0.12 mm offset along the slow axis, were averaged. The red arrow indicates a dark band inner to the ELM. b Linear-scaled, outer retinal zoomed-in view showing the newly visualized dark band (red arrow). c Contrast-enhanced zoomed-in view on a linear scale. d The ONL-normalized intensity of the dark band inner to the ELM (red brackets in b, c) is significantly different from 1 and from that of the inner segments (blue brackets in b, c) in six mice (The ONL region for normalization is denoted by green brackets in b, c). e The thickness of this dark band, taken as the FWHM of a fitted Gaussian, was ~2 μm in six mice. Error bars represent standard deviations across subjects (**p < 0.05). Note that no error bars are shown for the ONL in d due to normalization. (NFL: nerve fiber layer; GCL: ganglion cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; OPL: outer plexiform layer; ONL: outer nuclear layer; ELM: external limiting membrane; ISOS: inner segment/outer segment junction; OST: photoreceptor outer segment tips; RPE: retinal pigment epithelium; BM: Bruch’s membrane; Ch: choroid)