Ultrahigh speed spectral/Fourier domain OCT imaging in ophthalmology

Ultrahigh speed Spectral/Fourier domain ophthalmic OCT imaging at 70,000–312,500 axial scans per second is demonstrated using a high speed CMOS camera at 800 nm. Comparative imaging results of the fovea illustrate the performance tradeoffs between different imaging speeds and spectrometer configurations. Dense 3D volumetric acquisitions show minimal motion artifacts when acquired at 250,000 axial scans per second. The porous structure of the lamina cribrosa is shown in en face images extracted from a dense volumetric acquisition of the optical nerve head acquired at 106, 382 axial scans per second. Rapid repeated volume imaging (4D-OCT) shows blood flow in retinal capillaries. Boundaries of the capillary network are enhanced by motion contrast. 3D volumetric data acquired at 49,000 axial scans per second using an InGaAs camera at 1050 nm is compared to volumetric data acquired at 101, 010 axial scans per second using a CMOS camera at 800nm. Averaging of adjacent cross sectional scans in the volume is shown to increase contrast in the images and reduce speckle. The enhanced penetration of the 1050 nm compared to the 800 nm OCT imaging system is shown. Dense 2D/3D data sets and 4D-OCT repeated volume imaging promise alternative methods for diagnosis and monitoring of disease.