the author of this app says:
OptoDrum is an easy to use replacement for a bulky optokinetic drum or a fraying cloth tape to elicit optokinetic nystagmus for evaluation of neurological, otological, and opthalmological disorders. Simply place the iPhone with a moving pattern in front of a patients 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 pattern.
A left or right finger swipe switches a stopped pattern to the next one in rotation.
What's New in version 1.2.1
Added a second strip of animals rotated by 90Âș for vertical viewing.
- Requires iOS 3.0 or later