A drum-like ophthalmic device covered with alternating white and dark stripes or pictures. The device is rotated in front of the patient's eyes and is intended to elicit nystagmus (involuntary rapid movement of the eyeball). This is used to diagnose the patient and is particularly useful for babies and children who cannot communicate, e.g., if nystagmus cannot be induced, this suggests that the child suffers from impaired vision or blindness.