BACKGROUND INFORMATION

Some optical systems may benefit from capturing images of a user's eye. Head mounted displays (HMDs), for example, may perform eye-tracking functions which may enhance the user's viewing experience. Eye-tracking may be aided, in some cases, by illuminating the eye of the user and then capturing images of the illuminated eye. However, various contexts may generate challenges to capturing images of the eye that include sufficient contrast for analyzing the images. In particular, stray light may propagate through an optical system and be received by a camera and thereby increase the background noise for the light propagating along the desired imaging optical path.

