Full Idea
The traditional examples used to support the sense datum theory were seeing double and specks before one's eyes.
Clarification
'Sense data' are what come between objects and our experience of them
Gist of Idea
The traditional supports for the sense datum theory were seeing double and specks before one's eyes
Source
Tim Crane (Elements of Mind [2001], 5.43)
Book Reference
Crane,Tim: 'Elements of Mind' [OUP 2001], p.142
A Reaction
Presumably, though, direct realists can move one eye, or having something wrong with a retina.