US 12,446,776 B2
Compensating for polarization changes introduced by components with retardation in polarization-sensitive retinal scanning systems
Boris Gramatikov, Baltimore, MD (US); and David Guyton, Baltimore, MD (US)
Assigned to The Johns Hopkins University, Baltimore, MD (US)
Appl. No. 17/601,351
Filed by THE JOHNS HOPKINS UNIVERSITY, Baltimore, MD (US)
PCT Filed Apr. 6, 2020, PCT No. PCT/US2020/026840
§ 371(c)(1), (2) Date Oct. 4, 2021,
PCT Pub. No. WO2020/206414, PCT Pub. Date Oct. 8, 2020.
Claims priority of provisional application 62/829,307, filed on Apr. 4, 2019.
Prior Publication US 2022/0167845 A1, Jun. 2, 2022
Int. Cl. A61B 3/10 (2006.01); A61B 3/02 (2006.01); A61B 3/113 (2006.01); A61B 3/12 (2006.01); A61B 3/14 (2006.01)
CPC A61B 3/12 (2013.01) [A61B 3/102 (2013.01); A61B 3/113 (2013.01); A61B 3/14 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An optical system using a polarized light to interrogate birefringence properties of a retina of an eye in order to detect a fixation condition of the eye by sensing characteristic birefringence patterns of retinal structures, comprising:
a source of polarized light configured to emit the polarized light;
a double-pass imaging system to image the polarized light onto the retina and to capture a reflected light;
a scanning system to vary a location on the retina where the birefringence properties are interrogated;
a detection system wherein the detection system comprises a sensor, wherein the sensor is configured to detect polarization components, wherein the detection system is configured to analyze changes in a polarization state of the detected polarization components of the reflected light from the retina as a measure of an amount and an orientation of the retinal birefringence, and wherein the detection system is configured to determine the fixation condition of the eye based on the polarization state,
an optical system, wherein the optical system contains unwanted retardance, wherein the unwanted retardance can cause interference with polarization measurements which alters a polarization state of the polarized light entering the eye and of the reflected light reaching the detection system; and,
a compensating retarder provided in each of a forward and a return light path to nullify an effect of the unwanted retardance in each of the forward and return light paths so that polarization states of the polarized light entering the eye and the reflected light reaching the detection system are not contaminated by the effects of the unwanted retardance.