Ultra–High Speed and Ultra–High Resolution Structural, Flow Velocity, and Polarization Sensitive Sd/Fd–Oct of the Human Retina

Abstract

 

Abstract:

 

To demonstrate structural and functional cross sectionalimaging of the retina at video rate by Spectral Domain OCT (SD–OCT).Doppler analysis alllows measurement of blood flow velocityand pulsatility in arteries and veins. Polarization sensitivityallows depth resolved measurement of the RNFL birefringence.

 

A clinical OCT instrument was developed based on SD–OCTincorporating doppler flow velocity and polarization sensitivity.

 

 

In vivo OCT images were acquired at video rate (29 frames persecond) with better than 3 µm axial resolution. Artifactsdue to subject motion were significantly reduced, allowing mappingof true retinal topography. Doppler OCT allowed determinationof pulsatile retinal flow in arteries and veins, and quantitativedetermination of the cardiac cycle. Birefringence analysis allowedmeasurement of the RNFL birefringence around the ONH.

 

Functional SD–OCT allows for comprehensivescreening of large area’s and 3–D volume renderingof optic nerve head and fovea structure, vasculature and RNFLbirefringence. Accurate knowledge of retinal structure and bloodflow dynamics is important in not only the treatment but alsounderstanding the pathophysiology of many diseases, includingglaucoma.

 

 

^{Fig 1: Structural (left) and bi–directional Doppler image(right) showing flow in an artery–vein pair and in verysmall blood vessels.}

 

 

^{Fig 2: Ultra–high resolution SD/FD–OCT image ofthe fovea showing different layers. Circles indicate small bloodvessels.}

 

 

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • macula/fovea