Stratus-OCT Time-Domain is described by which statement?

• A. It Uses Stationary Reference Mirror and Analyzes the Spectrum
• B. It Has Higher Resolution Than Spectral-Domain
• C. It Cannot Image Retina
• D. It Uses Moving Reference Mirrors to Capture the Image

Answer: (D)

Time-domain OCT relies on sampling depth by mechanically varying the reference arm with a moving mirror. As the mirror scans, the optical path length changes, so interference occurs from different depths in the retina. Each mirror position corresponds to a specific depth point, and collecting the interference signal across the sweep builds up an A-scan; combining many A-scans yields a cross-sectional image. This moving-mirror approach is what gives TD-OCT its time-domain name and distinguishes it from Fourier-domain methods, which keep the reference path fixed and extract depth information from the detected spectrum. Stratus-OCT uses this moving-reference-mirror technique to capture retinal images.