OptoDrum is an easy to use replacement for a bulky optokinetic drum or a fraying cloth tape to elicit optokinetic nystagmus, OPK or OKN, for evaluation of neurological, otological, and opthalmological disorders. Simply place the iPhone with a moving pattern in front of a patient's eye to elicit the response. The stripe pattern, width, and speed are easily adjustable.

• OptoDrum provides five patterns: black stripes, red stripes, mixed colors, symbols, and animals.

• Drag a finger up or down the screen to make the pattern move at the speed of your finger.

• Double tap the moving pattern to make it stop.

• Pinch or zoom the pattern with two fingers to narrow or widen the stripes or symbols.

• A left or right finger swipe switches a stopped pattern to the next one in rotation.