A model eye includes an optically transmissive structure having a front curved surface to receive a coherent light beam, and an opposite rear planar surface for directing a portion of the coherent light beam back out the model eye through the front curved surface； and a material structure adhered to the rear planar surface of the optically transmissive structure that has a characteristic to cause a speckle pattern of the portion of the coherent light beam that is directed back out the front curved surface of the optically transmissive structure to have a bright-to-dark ratio of less than 2:1. In some embodiments, the material structure may include a fabric-reinforced polyethylene tape adhered to the rear planar surface of the optically transmissive structure by an adhesive. One example material structure which may be employed is duct tape.
