DEVICE: Clip-on Spielmann (B091121310)

A thin, plastic, flap-like device that is clipped onto the upper frame of a pair of existing spectacles (eyeware) to block vision through the spectacle lens. It is typically made of plastic and is available in preformed, leaf-shaped, disks, usually with a pair of clip on hinges on its top edge; it is subsequently applied to the exterior of the lens. The device is often used for children and is intended to be used prophylactically (e.g., to prevent amblyopia -- impairment of vision without apparent disease) and/or therapeutically [e.g., to treat squinting, double vision (diplopia), and problems due to absence of a natural lens (aphakia)]. This is a reusable device.