A first optical subsystem includes a window with a refractive index nw and an exit lens having a refractive index nx. The exit lens is configured to couple to the window to define a first optical axis extending through the window and the exit lens. A second optical subsystem is configured to output a light beam. The light beam is directed to be incident at a convex surface of the exit lens along a second optical axis at an angle α that is offset from the first optical axis. The window is configured to detachably couple to the cornea of the eye such that the first optical axis is generally aligned with a direction of view of the eye. The respective refractive indices nw and nx are configured to direct the light beam incident at the convex surface of the exit lens through the cornea of the eye toward the irido-corneal angle.