|United States Of America||Issued Patent||9,427,147||08/30/2016||2012-007|
Optical Coherence Tomography provides anatomical structure of ophthalmic tissue based on its reflectance properties as imaged from a single pupil entry position. This entry position serves as a pivot point for the beam to be scanned back and forth along a single arc. While current OCT is sufficient to determine the structure of many retinal layers, it does not routinely permit identification of the boundary between the anatomical layer containing the photoreceptor nuclei (outer nuclear layer) and their axons (Henle’s fiber layer).
To meet these challenges, investigators at the University of California have developed an directional optical coherence tomography (dOCT) system which introduces an additional element into the path of the OCT beam. The dOCT system allows the OCT beam position to be steered towards eccentric pupil entry positions. When this element is rotated about its long axis displacing the beam while maintaining the overall direction of the rays and causes the OCT beam entry position to shift. Scanning galvos can be used to rapidly rotate this element. The other changes visible with an dOCT beam entry position changes in normal eyes and in eyes with pathology of clinical importance.