Described embodiments include systems and methods for acquiring iris biometric data. An optical entrance of an optical medium may receive a ray incident on the optical entrance, the ray comprising biometric data. An interface of the optical medium with a second medium may receive the received ray at a first angle greater than a critical angle of the interface to enable total internal reflection of the received incident ray. A reflective coating, prism or other mechanism may be used in place of the interface to redirect the received ray or bend the optical path of the received ray. An optical exit of the optical medium may couple the reflected or redirected ray to a sensor for acquiring the biometric data. The ray may be incident on the optical entrance at a second angle relative to an axis of the sensor that is less than 90 degrees.