Archive for July, 2010

Éowyn L. F.


It is impossible in our current stage of technological development to avoid the rise of 3D media; it is present in the movie theatres, video games, and now in our homes. 3D technology is relatively new, and is continuing to advance as research progresses. To create a three-dimensional image on a two-dimensional television screen, scientists have discovered a way to take advantage of the ways our eyes naturally function to “trick” our brains into believing that the flat images displayed on the screen have depth. This process brings great delight to many movie goers, but may also have some health risks as well.

As young children we are born with a visually “blank slate” similar to an empty hard drive; as we grow and develop we must fill that hard drive with the information that tells us what normal vision should be like. As adults we do not see “one great blooming, buzzing confusion,” but rather we are pre-programmed as infants to learn to see naturally the three-dimensional world around us, with no special training or instruction. Babies slowly learn to identify and recognize faces, patterns, and will continue to do so until they are able to properly navigate their world and to accurately name and categorize things. Humans, more than any other creature, have an incredible sense of depth perception, due to the development of stereopsis; the ability to perceive the world in three dimensions due to the two slightly different projections of the world onto the individual retinas of each eye. When using both eyes simultaneously it is known as binocular vision. You will find that if you close one eye, and then open the other (while closing the first) the position of what you are looking at seems to change; this difference in the location of an object viewed along two different lines of sight is called parallax. 3D technology, or stereoscopy, exploits the normal functions of our brain to create an illusion of depth by presenting a different image to each eye.

There are four primary methods of presenting a three-dimensional image on a two-dimensional surface; anaglyph, polarized lenses, active-shutter glasses, and autostereoscopic display. The anaglyph method uses filtered lenses to create the image; this is one of the more popular methods. The viewer wears 3D glasses with cyan and magenta filters while watching a 3D movie; a different image goes to each eye, and one image goes to both. If you take off the filtered lenses you can see the cyan and magenta “silhouettes” around the main image on the screen. The second method is to use polarized lenses; by restricting the amount of light that reaches each eye, this form of stereoscopy exploits the natural polarization of light. The polarized filters block light polarized in the opposite direction, but allows light that is similarly polarized to pass through to the eye, thus presenting the viewer with two different perspectives of the film simultaneously. A third pair of glasses, which are not commonly used due to high costs and negative effects, are active shutter glasses. The media of choice is displayed at a very high frame rate (the frequency which unique consecutive images are produced by any media display) while the glasses quickly alternate between being clear and black, using a pair of low-latency transparent LCD screens. (Low-latency allows the delays to be nearly unnoticeable to the human eye.) For a very brief period of time one eye sees the proper image displayed, while the other eye sees nothing. It is unlikely that someone in the general population has used these glasses; high cost of production and the risk of theft cause them to be impractical until they are much improved. The last mainstream method of 3D production, autostereoscopic display, does not require the use of glasses. This method is similar to the “holographic” displays (and transforming images) seen on CD covers and trading cards. The idea is that one pixel (or group of pixels) has its light directed into one eye while the other eye receives the light from a different group of pixels. There are multiple ways to achieve this goal, but one of the most frequently used methods is a parallax barrier: a series of specifically placed slits in the display allows light from every other line of pixels in the display to go in a different direction than the adjacent line.  While this enables the viewer to enjoy the three-dimensionality without the use of glasses only a limited number of people can look at the display at the same time, otherwise the images are not displayed accurately.

While attending a movie or playing a video game in 3D may be enjoyable for some, there are also several negative consequences that must be considered. Some of these issues are effective immediately after viewing the 3D media, some involve those individuals who cannot enjoy three-dimensional imaging, and others are problems will need to be addressed as our homes become 3D media stations in the near future. One of the greatest dangers to a specific area of 3D viewing are those associated with Samsung’s active-shutter glasses. The glasses cause each eye to be completely blocked out between thirty to sixty times per second, the equivalent to being exposed to a high-frequency strobe light; this can be the cause of seizures and similar effects such as nausea and fatigue. . If you hold your finger close to your face and look at it, you will notice that the background seems fuzzy; this is because it is out of focus. When you intentionally focus your eyes on something directly behind your finger, those objects will become clear and your finger will become blurry. You will also notice a slightly unusual feeling in your eye: this is because your iris, which is a muscle, is causing the lens of your eye to change shape so that the object you wish to view is clear and in focus. Because our ability to bring an object into clear focus is determined by our irises’ ability to adjust the shape of the eyes’ lenses, the constant blocking out of alternating eyes may also lead to eye strain, specifically of the lens and iris.

The primary concern when viewing 3D media is that, not only are you tricking your eyes into perceiving depth where there is none, but you are also tricking your brain. When you see a person or object in a movie or video game, your eyes immediately attempt to bring the item into focus by deforming and adjusting your lenses. When nothing changes, your eyes will continue attempting to refocus the image, causing tension in the eye muscles and confusion in the brain; this will keep occurring every time the shot changes, or when the characters and or camera move. Because we learn to perceive depth as children by interacting with the world in the natural way, there is also potential for the visual lessons you learned as a child to be unlearned. There have been many reports over the years of people having depth perception problems immediately after watching a 3D movie or interacting with a video game in 3D. (People have also reported developing headaches and nausea from three-dimensional movies.) Since it is unlikely that the general populace will be overexposed to this type of entertainment, there is little cause for concern among adults; however, for young children who do not yet have established visual systems there is potential for the growth of stereopsis to be stunted, particularly for those aged seven and under. A child who is exposed to excessive amounts of 3D media on a 2D screen may develop incorrectly due to the misleading stimuli that guides the brain into thinking this 3D/2D vision is normal. Again, children are not often exposed to entertainment of this nature, but with the expansion and lowering costs of technology, there may soon be a 3D television in every home.   An example of the deleterious effects of 3D technology on children can be seen in Sega’s Virtual Reality creation headset; this headset was a wraparound LCD screen with headphones depicting a 3D environment that they player could interact with. Studies conducted at the Stanford Research Institute revealed that this virtual reality could cause stereopsis in children, leading them to develop strabismus, a condition in which the eyes are not properly aligned with each other. There are few ways to prevent the issues mentioned here, except for limiting exposure to the media in question, as well as taking breaks (if possible) as one might when working on a long computer project. Children’s access to 3D displays should be limited in particular, or some people may choose to avoid three-dimensional movies and games entirely until the technology improves.

Another concern, from an economical point of view, is the discovery that approximately thirty percent of the population suffers from marginal binocular vision; their eyes don’t work and focus together as they should. If a person’s eyes have an inability to coordinate their vision correctly, the proper stereoscopic effect will not be achieved; those who can see the effect without issue are referred to as being stereo-acute. In our society there are quite a few individuals who have minor eye problems to begin with; these the brain will deal with naturally, under normal circumstances; however, when confronted with a new sensory experience (3D on a 2D surface) the brain and eyes must work harder to focus properly and correct the issue, making the development of headaches more likely. Dr Deborah Friedman, a professor of ophthalmology and neurology at the University of Rochester Medical Center in New York, comments “The illusions that you see in three dimensions in the movies is not exactly calibrated the same way that your eyes and your brain are. If your eyes are a little off to begin with, then it’s really throwing in a whole other degree of effort that your brain now needs to exert.” People who have pre-existing eye muscle problems may have trouble processing 3D images, or may not be able to see the image correctly at all. Somewhere between two and twelve percent of all viewers are unable to appreciate this popular form of entertainment; they are either unable to see the effect at all, or may become ill due to viewing the images. If a person cannot see the effect, they may have what is termed monocular vision (also referred to as being stereo-blind). Stereo-blindness may be caused by disorders preventing the eyes aligning/focusing correctly, or by a loss of vision in one eye.

While so far there have been only minor issues and side-effects concerning 3D imaging, the technology is swiftly advancing and the potential hazards cannot be ignored for long. As three-dimensional media slowly creeps into our homes and lives, exploiting the natural function of our eyes and tricking our minds, the risks associated will soon need to be addressed. As it is now, society can be content to enjoy this wonderful form of entertainment, so long as they limit their exposure, supervise children in the use of 3D media, and become aware of the possible side effects of prolonged exposure to three-dimensional movies and games.


Coldewey, Devin. “A Guide to 3D Display Technology: Its Principles, Methods, and Dangers.” CrunchGear.  TechCrunch Network, 06.19.2010. Web. 1 Jul 2010. <http://www.crunchgear.com/2010/06/19/a-guide-to-3d-display-technology-its-principles-methods-and-dangers/ >.

Polarized Lenses, Stereoscopy, Parallax, Strabismus, Depth Perception. Wikipedia. Retrieved (2010, July    1) from http://en.wikipedia.org/wiki/Main_Page

Steenhuysen, Julie. “For Some, 3D Movies a Pain in the Head.” Reuters (2010): n. Web. 2 Jul 2010. <http://www.reuters.com/article/idUSTRE6080XO20100109&gt;.

Owen, Dave. “Stereo-Blind: People who can’t see 3D.” MediaCollege. Wavelength Media, 01.19.2010. Web. 2 Jul 2010. <http://www.mediacollege.com/3d/depth-perception/stereoblind.html&gt;.

Raad, Dominic. “3D Entertainment > Depth Perception.” Skatter Tech. oneRefresh, 06.29.2010. Web. 2 Jul 2010. <http://skattertech.com/2010/06/3d-entertainment-depth-perception/&gt;.


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