"Spinning before the eyes" is a frequent complaint. Interpretation is not always straight-forward and particularly so if the patient is symptom-free at the time of consultation. Dynamic simulations may be helpful to identify major types of vertiginous vision. Select among the various types of image movement to try to find a match with the perceived movement. There are no adjustable parameters. Select "Off" to stop movement.
Double vision also may be difficult to interpret if the patient is asymptomatic at the time of the examination. The following display might help to identify the nature of the complaint. Left-click on the target and move the mouse cursor to see how a copy of the target can be moved around on the screen. Note that the copy appears more indistinct, the larger the distance from the center, just like the "false" image in real double vision. In real life, the false image often appears rotated. Right-click the mouse and use small vertical mouse movements to effect rotation. Alternate left and right mouse clicks to refine the target's position and orientation. Tap keyboard key F5 to reset.
To obtain permanent records from these displays, tap the PrintScreen keyboard key, open a paint programme, and import the Clipboard. The screen image can then be cropped as necessary and saved in a variety of formats.