Three–Dimensional Fourier Domain OCT of Age–Related Macular Degeneration: Comparison With Conventional OCT

Abstract

Purpose: : To demonstrate a new emerging technology of three–dimensional fourier domain optical coherence tomography (FD–OCT) for visualization of pathologic lesions in age–related macular degeneration.

Methods: : Thirty four eyes with age–related macular degeneration (ARMD) were examined with FD–OCT, and simultaneously examined with conventional, commercially available time domain OCT (TD–OCT) in all cases. The spectrometer–based FD–OCT system, whose acquisition time is 27 ms for a single B–scan (transverse 1024 A–scans) or 3.5 s for a single OCT volume consisting 256 x 256 A–scans, was employed for the study. This system was combined with a fundus camera for monitoring patient’s eye. Three–dimensional (3–D) imaging was performed with sensitivity of 97dB and depth–resolution of 6.1 µm in tissue, with a superluminescent diode (SLD) which has the center wavelength of 830 nm and the band width of 50 nm. For realistic 3–D images, fast and simple correlation–based algorithm was employed for canceling the motion artifact of patient eyes.

Results: : FD–OCT could provide more clear images of B–scan of epi–, intra–, subretinal–, and sub RPE levels than conventional TD–OCT. Precise delineation of the configuration of the macula was achieved. But under PED structure, especially serous PED, FD–OCT provide few information. The high contrast 3–D imaging allows the acquisition of the virtual image of architectural morphology of the choroids, and two layers was detected under RPE structures. High contrast and speed of FD–OCT system made clinically available relatively clear images in eyes with dense cataract or dense after cataract or in eyes having difficulty in fixation, which was not able to perform with conventional TD–OCT.

Conclusions: : High contrast B–scan and 3–D images of ARMD by high–speed FD–OCT provide comprehensive visualization and mapping of chorioretinal pathologic structures. Availability for high resolution and high contrast images of not only epi–, intra–, subretina but also the structure beneath RPE in all cases is feasible for understanding ARMD clinicopathological issue, especially initial stage.

Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)