The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 21, 2025
Filed:
Apr. 06, 2020
The Johns Hopkins University, Baltimore, MD (US);
Boris Gramatikov, Baltimore, MD (US);
David Guyton, Baltimore, MD (US);
The Johns Hopkins University, Baltimore, MD (US);
Abstract
An optical apparatus uses polarized light to interrogate birefringence properties of the retina to detect the fixation condition of the eye by sensing characteristic birefringence patterns of the retinal structures. Optical components, as well as optional additional components, interfere with the polarization measurements by introducing unwanted retardance which alters the polarization state of the light entering the eye and of the light reaching the detection system. Compensating retarders are provided to nullify the effect of unwanted retardance in the forward and return light paths so the polarization states of the light entering the eye and the light reaching the detection system are not contaminated by the effects of the unwanted retardance. Mueller matrices are used to mathematically calculate the parameters for the compensating retarders for the unwanted retardance. A variable retarder system may also be provided to compensate for the corneal birefringence of the eye via feedback control.