At the dawn of the new millennium, virtual reality (VR), the computer simulation of visual information, is revolutionizing the way we see, learn about and analyze the world around us. From the earliest versions of three-dimensional virtual reality a century ago to our current interactive computerized video games and the many practical applications of this developing technology, we have been transported into rich virtual worlds, where knowledge is far easier for the human brain to understand. However, the health hazards associated with the recreational use of 3-D VR are worth noting.
3-D Virtual reality
Imagine taking a tour of the human body and its internal organs, walking beside a brontosaurus or soaring at will through the solar system. In the 3-D world of virtual reality (VR), all this and more is possible. And all thanks to technology that dates back to 1838!
That’s right! It was in 1838 that Sir Charles Wheatstone invented the stereoscope, a popular 3-D viewer. This wood and metal viewer had special angled lenses and an adjustable card holder that sat in front of it. Stereographic cards featured two side-by-side images that simulated views from slightly different angles, as seen by each human eye. In looking through the viewer, the brain would fuse the two different images into one, thus creating the illusion of three-dimensional viewing.
Today, 3-D VR technology uses the same principles with the head-mounted display (HMD). Inside 3-D HMDs, two computer screens direct displays from slightly different angles at each eye. The result is not only 3-D vision, but the impression that we have actually been transported to another world!
Virtual environments deliver the power of the computer, the data of an encyclopedia, the imaging of animation and the 3-D characteristics of real life. Playing 3-D VR arcade-type games is more exciting and calls upon more of our faculties than simple flat-screen video games because most of our brain is engaged in producing a full-scale sensory illusion. Popular VR technology includes 3-D sound and some kind of joystick or controls. But gloves that simulate touch sensations and motion tracking are in the offing for second-generation VR products.
We learn more and better when we see in three dimensions and when our other senses are engaged. In educational, research and demonstration simulations, virtual reality allows us to visualize, manipulate and interact with computers and extremely complex data in a revolutionary, hands-on way.
The applications of VR technology are ever-expanding. Architects can take clients on virtual tours of buildings before they are built. Automotive and airline engineers use VR to design machinery and parts, thus minimizing wasteful physical trial runs. Workers can then use the same technology to train before they operate new machinery, saving time on the production line. VR can also be used in teleconferences, virtual surgery or simulated military exercises. And people with disabilities can use VR as a means of interacting with able-bodied people within a simulated universe.
Recreational 3-D VR users should be aware of the side effects of VR use, especially on children. Since our eyesight continues to change until we reach our early 20s, and users experience problems with distance focusing after VR simulations, exposure should be limited to avoid vision difficulties.
Adults should not play 3-D VR games any longer than 15 minutes at a time, with rest periods in between. Conflicting motion signals from the eyes, the inner ear and the rest of our sensory systems, and visual lag in the movement of virtual surroundings can cause disorientation from sensory overload, serious temporary visual deficits and potentially disabling symptoms that resemble motion sickness.
In fact, our eyes accommodate differently to VR scenery than to real life. In VR, objects appear closer or farther than they really are, which means that our internal eye muscles as well as our external ones, those that control convergence, are working with unusual intensity. As a result, our eyes may move at an alarming speed in all directions, notably in 3-D fiction games (e.g. video games featuring superheroes). How do we manage to keep up with such intensity? Our brain can create the illusion of distance (objects appearing closer or farther then they really are) by correcting and interpreting our accommodation level and the reverse is true when we step out 3-D VR to head back to the “real” world.
A word of caution: it may take some time (minutes for some, hours for others) to regain visual and physical balance.
A word to the wise: VR users should refrain from driving or performing other exacting visual tasks after simulations and should be accompanied by persons who have not engaged in VR simulations on the same occasion. Because of the inherent flashing of display screens, epileptics should avoid VR games, since they may induce seizures. The adverse effects of close-up exposure to the electromagnetic radiation of HMD screens has yet to be fully assessed and publicized.
For more information
Stereoscopy: http://www.logantele.com/~phillips/moreinfo.htm
HMDs: http://www.thevrsource.com/binocular.htm
Health hazards: http://www.aoanet.org
http://www.sola.com/professional/techtips/tip5.html
Futuristic applications: http://members.tripod.com/engineer161/virtual_reality.htm
3-D VR and children’s vision and adverse side-effects: http://www.aoanet.org
Sources
http://www.healthatoz.com
http://www.pbs.org
http://encarta.msn.com/find
