The two eyes obviously see from a different angle and hence the brain has to combine them in order to perceive a single coherent image.
Just a few minutes ago, while reading in bed, I got distracted by something in my right eye and it turned out to be a red LED of the DVD player just to the right of the book in my visual field. The LED is hidden to my left eye. So just for kicks, I tried to “merge” the two images and voila, after a couple of seconds of trying, I see the LED in the middle of the right page. It’s disorienting, so I didn’t hold the merged image for long. Is this harmful? What’s the harm?
i’m not an optician, but i can’t imagine how it coule be harmful.
graphic designers, film makers, theatre lighting and set designers, retail displays etc… use variations on paralax illusions (what you experienced) all the time to distory our perception of spacial relationships.
essentially you just made you own personal stereogram.
i’m a sound engineer for a living, and i have this habit when i’m listenig to a mix of staring PAST the rows of identical knobs and faders on my board until i trick my eyes into resolving the wrong rows together, (left eye is focusing on say channel 12, and right eye is focusing on row 13, but they think they’re both looking at the same row- if that makes sense) so that the board looks MUCH closer and bigger than it actually is. you can do the same thing by looking “past” and significantly large vertically alligned pattern. entirely useless, but keeps my eyes occupied with my ears are workin.
If it were in any way harmful, then the makers of those “Magic Eye” pictures would have gone out of business, and there would be warnings all over the posters.
In vision psychophysics, this is called the “cheshire cat illusion.” If you try to read the page, the LED will disappear, and if you try to see the LED, the region of the page surrounding the LED will disappear.