A light based system for treating an eye includes a mask that is configured for positioning on the eye and a light source that is configured to deliver therapeutic light. The mask has an inner surface that is positionable against the eye and an outer surface that is opposite the inner surface. The mask is optically opaque to prevent transmission of light through the mask and the mask includes at least one transparent opening that allows transmission of light through the mask to target tissue of the eye posterior the transparent opening. The light source is positioned relative to the mask so that the delivered therapeutic light irradiates at least a portion of the mask and the transparent opening. Therapeutic light traverses through the transparent opening to the target tissue positioned posterior the transparent opening.
