Optical Coherence Tomography What is Optical Coherence Tomography

Optical Coherence Tomography

What is Optical Coherence Tomography? Tomography: - Comes from the Greek word Tomos, which means section. - cross-sectional images of the retina. - as opposed to topography which only shows contours of the surface of the retina.

Optical Coherence Tomographer - Based on the Michelson Inferometer - Developed by Albert A. Michelson in 1878. - works by comparing the phase relationship (or interference) of one beam of light to a reference beam of light.

Michelson Interferometer Source Moveable Reference Mirror Xref Eye under Test Xsample Beamsplitter Detector Output Signal

Stratus OCT Vitreous Z axis: 1024 data points over a 2 mm depth with resolution of approx. 10 microns 1024 X-Y axis: repeated 128 to 512 times 1024 512

The retina

The retina Internal limiting Membrane Nerve Fiber Layer Retinal Ganglion Cell Layer Outer plexiform layer Inner nuclear layer : horizontal, bipolar amacrinre cells Inner plexiform Layer Photoreceptors RPE

Cross-section of the retina NFL ILM GCL IPL OPL Stratus OCT™ IS/OS RPE/CC IS/OS: Junction of inner and outer NFL: Nerve Fiber Layer ILM: Inner Limiting Membrane photoreceptor segments RPE: Retinal Pigment Epithelium GCL: Ganglion Cell Layer CC: Choriocapillaris Choroid IPL: Inner Plexiform Layer OPL: Outer Plexiform

Shadowing - blood vessels - other object blocking light

Common scan types

Normative data display

Normative data display

Anterior chamber OCT

Spectral domain OCT Spectrometer Time Domain OCT Spectral Domain OCT

Spectral domain OCT