Conventional (top) and ultrahigh-resolution (bottom) in vivo OCT images along the papillomacular axis. The log of the backscattered light intensity (from 5 to 45 dB) is represented on a false-color scale. Axial resolution is 10 μm (top) and 3 μm (bottom). The image sizes are 8.46 × 0.95 mm (transverse × axial, top) and 8.43 × 0.82 mm (bottom). The image has been expanded by a factor of two in the axial direction. Conventional and ultrahigh-resolution OCT images were acquired with 100 × 180 (transverse × axial) and 600 × 725 pixel sampling, respectively. This corresponds to a pixel spacing of 84.6 × 5.2 μm (transverse × axial) and 14.1 × 1.1 μm, respectively. The nerve fiber layer is well differentiated and varies in thickness between the fovea and optic disc.

Comparison of an in vivo ultrahigh-resolution OCT image (top) of the normal human macula to a histologic micrograph of the normal macula (bottom) taken from an ophthalmic textbook26. The OCT image has 1:1 aspect ratio to permit comparison to histology. Several layers can be resolved and have been labeled in the image: Inner limiting membrane (ILM), nerve fiber layer (NFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), junction between the inner and outer segment of the photoreceptors (IS/OS PR), outer nuclear layer (ONL), retinal pigment epithelium (RPE). The foveola, fovea centralis, as well as the parafoveal region, are also indicated. (Histological micrograph reproduced with permission from Stereoscopic Atlas of Macular Diseases: Diagnosis and Treatment26.)

Quantification of intraretinal structures. a, Image-processed, segmented OCT image of the fovea. b, Corresponding plot of thickness of the retinal layers. c, Plot of thickness of retinal layers along the papillomacular axis. (The segmented OCT image of the papillomacular axis is not shown, but similar to that in Fig. 1.) The tomogram has been expanded by a factor of three in the vertical direction for better visualization of the retinal substructure. The measured thicknesses of the segmented layers (except the RPE and choroidal layers) are plotted as a function of transverse position (b and c). Clear visualization and quantification of the NFL is especially important for glaucoma diagnosis (c). NFL thickness increases towards the optic disc with a corresponding reduction in the thickness of the GCL and IPL layer towards the optic disc (see c). Choriocapillaris (CC); choroidal layer (CL); ganglion cell layer (GCL); inner plexiform layer (IPL); inner nuclear layer (INL); internal limiting membrane (ILM); nerve fiber layer (NFL); outer plexiform layer (OPL); photo receptor layer (PRL); retinal pigment epithelium (RPE); retinal thickness (RT).

In vivo ultrahigh-resolution corneal OCT image of a normal human subject. The image has 6 × 2 μm (transverse × axial) resolution. The image size is 1.1 × 0.8 mm (transverse × axial) with 600 × 800 pixels, corresponding to 1.8 × 1 μm pixel spacing. The corneal epithelium, Bowman’s layer, intrastromal morphology and endothelium can be visualized. Boxes show enlargement by a factor of two and correspond to matching shapes in large figure.

Ultrahigh-resolution ophthalmologic OCT system using a titanium:sapphire laser light source. The interferometer was dispersion balanced (using H₂O water; BK7 glass; FS fused silica) and optimized for ultrabroad bandwidths to achieve axial resolutions of 2–3 μm. Polarization paddles (PC polarization controllers) were used to control incident polarization. The system was interfaced to a slit-lamp biomicroscope to permit simultaneous OCT imaging and en face retinal viewing.