Seems, it is now possible to find out what exactly a person was looking at if you just analyse a high-quality photo including the eyes.
'Shree K. Nayar, a professor of computer science and co-director of the Columbia Vision and Graphics Center, took high-resolution photographs of people that include their eyes and, in particular, the transparent part of the eye called the cornea. Then, with a postdoctoral researcher, Ko Nishino, he devised computer algorithms that analyze the images reflected in these natural mirrors, revealing a wealth of information ...
Dr. Nishino and Dr. Nayar plan to try their corneal imaging system with archival photographs. "It will be fascinating to go back and look at photographs of important people like John Kennedy," Dr. Nayar said. "From a single image of the eye, we may be able to figure out what was around him and what he was looking at.'
So, when you take your next portrait, just think that you may actually also produce an image of yourself, the photographer!
Adjust your clothes before pushing the trigger and wear dark sunglasses when someone takes a photo of you in surroundings you do not want the world to see...
One further interesting aspect: who owns the copyright to an image extracted from a photo?