A display system comprising: projection optics (101, 210, 612, 1015) configured to project a beam of light in a first direction; an eyepiece unit (100, 300, 500) including: a first waveguide layer (530, 620, 710, 810, 1036) disposed in a first lateral plane and including an incident light surface and an opposing surface opposite the incident light surface; an incoupling diffractive optical element (107, 242, 252, 262, 310, 532, 622, 712, 812, R1, R2) disposed on the incident light surface, wherein the incoupling diffractive optical element is configured to: incouple a first portion of the beam of light and to redirect the first portion of the beam of light in a second direction, wherein the first portion of the beam of light propagates in the first waveguide layer by total internal reflection; and transmit a second portion of the beam of light along the first direction; and a retroreflector (550, 624, 714, 816, 1040) disposed adjacent the opposing surface, wherein the retroreflector is configured to retroreflect the second portion of the beam of light along a reflected direction opposite to the first direction, characterized in that the incoupling diffractive optical element is configured to diffract at least a portion of the retroreflected beam of light in the second direction. projection optics (101, 210, 612, 1015) configured to project a beam of light in a first direction; an eyepiece unit (100, 300, 500) including: a first waveguide layer (530, 620, 710, 810, 1036) disposed in a first lateral plane and including an incident light surface and an opposing surface opposite the incident light surface; an incoupling diffractive optical element (107, 242, 252, 262, 310, 532, 622, 712, 812, R1, R2) disposed on the incident light surface, wherein the incoupling diffractive optical element is configured to: incouple a first portion of the beam of light and to redirect the first portion of the beam of light in a second direction, wherein the first portion of the beam of light propagates in the first waveguide layer by total internal reflection; and transmit a second portion of the beam of light along the first direction; and a retroreflector (550, 624, 714, 816, 1040) disposed adjacent the opposing surface, wherein the retroreflector is configured to retroreflect the second portion of the beam of light along a reflected direction opposite to the first direction, characterized in that the incoupling diffractive optical element is configured to diffract at least a portion of the retroreflected beam of light in the second direction. a first waveguide layer (530, 620, 710, 810, 1036) disposed in a first lateral plane and including an incident light surface and an opposing surface opposite the incident light surface; an incoupling diffractive optical element (107, 242, 252, 262, 310, 532, 622, 712, 812, R1, R2) disposed on the incident light surface, wherein the incoupling diffractive optical element is configured to: incouple a first portion of the beam of light and to redirect the first portion of the beam of light in a second direction, wherein the first portion of the beam of light propagates in the first waveguide layer by total internal reflection; and transmit a second portion of the beam of light along the first direction; and incouple a first portion of the beam of light and to redirect the first portion of the beam of light in a second direction, wherein the first portion of the beam of light propagates in the first waveguide layer by total internal reflection; and transmit a second portion of the beam of light along the first direction; and a retroreflector (550, 624, 714, 816, 1040) disposed adjacent the opposing surface, wherein the retroreflector is configured to retroreflect the second portion of the beam of light along a reflected direction opposite to the first direction, characterized in that the incoupling diffractive optical element is configured to diffract at least a portion of the retroreflected beam of light in the second direction.