An electrically-powered ophthalmic device intended to for the evaluation and training of a patient's binocular function, i.e., the ability of the two eyes to focus on a single object. It is used for diagnosing strabismus (squint), a deviation of the eye which the patient cannot overcome and present in variants such as stereoscopy (vision in depth), amblyopia otherwise known as lazy eye (dimness of vision without apparent disease of the eye), and diplopia [exotropia (outward eye deviation) or esotropia (one or both eyes turn inward)]. It typically consists of a base with twin vision tubes (adjustable in many axes) providing images and illumination.