1. A method to image the choroid of an eye, the method comprising: transclerally illuminating the choroid by propagating a substantial portion of incident light through the sclera of the eye, the incident light having a wavelength spectrum in the near-infrared region and the sclera acting as a waveguide to guide, substantially through total internal reflection, the incident light to illuminate the choroid from the rear of the eye; and obtaining a transmission image of the choroid by collecting the light passing out through the choroid and the pupil of the eye using an image sensor.