Virtual reality can work for those with one functional eye - Here's how

Before we get into how it happens, let's go to the source of the problem. Why do we think that users with one functional eye cannot enjoy the full VR experience?

The 3D movie experience

The idea that users with one functional eye will miss out on VR comes from our previous experience with another virtual reality format, the 3D movie. Even those with two perfectly functional eyes do not enjoy a 3D movie experience if the 3D glasses are not put on properly.

While watching a 3D movie, we have probably all tried to remove our glasses to experience the movie in its actual format and then put the glasses back on almost immediately. This is because the 3D movie projection relies upon our binocular vision to deliver the experience.

There are different types of 3D movie technologies. One type uses a fusion camera system which is designed to capture two sets of images at once. Another system uses a rig with two separate cameras for all shots. The old-style 3D movies that used red and blue glasses tinted one set of images red and the other blue. The glasses then filtered the images so that each eye see only one image. The brain processes the images as two perspectives of the same object, creating the illusion of a 3D image.

Many modern 3D movies, however, use polarization. In this case, a filter in front of the projector changes the polarization of each image to match the filter on either the right or left lens of the glasses. Again, the brain processes the images as two perspectives of the same thing - giving a 3D view.

In both cases, for individuals who cannot use one eye, the intended projection does not happen, and the experience is soured.

However, in virtual reality, using modern-day headsets, this problem does not occur.

How does VR work in headsets?

Modern-day VR headsets, such as the Meta Quest Pro, use two different displays to project three-dimensional computer-generated images to deliver a highly immersive environment that our brain perceives as real.

Unlike 3D movies that rely only on binocular vision to create the intended effect, VR headsets use a wide range of technologies, ranging from spatial audio to eyeball tracking, to create the virtual world around us. Since even one functional eye can receive and transmit these images to the brain for perception, the VR experience with one eye is not as affected as it would be with a 3D movie.

In both 3D movies and VR headsets, binocular vision can help us perceive depth. However, that's not the only way to perceive depth. For example, when driving in a car, it appears as though nearby features move rapidly and far away features move slowly. This is the perception of depth using parallax — the observed displacement of an object caused by the change in the observer's point of view

Our own knowledge of the world also helps us perceive depth. For instance, a dog inside a car may appear bigger than a building outside the window. Since we know that dogs are not bigger than buildings, we also know that the dog is closer while the building is further away.

The VR experience does not rely on one technology alone, and users can expect a realistic experience while using the headset. However, because the technology was designed and developed for users with two functional eyes, there are some things that users with only one eye, or sight in only one eye, will miss out on.

What will you lose when you use VR with one eye?

Different apps or games are designed differently to deliver the most immersive experience, but some use two displays to deliver 3D. In some cases, the user interface (UI) elements may be locked onto the head movement. This would mean that even if you turn your head, you will never be able to see the images displayed on the other screen. However, in apps where the UI elements are not locked this way, a simple turn of the head should be sufficient to know what's happening on the other display.

While this might sound a bit difficult for most, users with one functional eye would not find the VR world any different from their real world. The compensation required to experience VR will not be very different from those used to experience the real world. Users might have to turn their heads to see things on the blind side just like they do in the real world. However, since the field of view of VR headsets is still small, the compensation needed in the VR world will also be lesser.

There could also be small issues with the perception of the image quality since the single display image can only sharpen images to a certain extent, but it should not ruin the VR experience. Instead, there are a few things one can do to improve the experience instead.

What can be done to improve the experience?

To ensure that you don't feel short-changed by the VR experience, make sure you try out the technology before you spend your money on it. Instead of shopping for the headsets online, walk into a store and use the demo headsets there to get a feel of what using the device will be like for you.

This might not be the easiest way out and take some additional time, but it will be totally worth it since you will know exactly what to expect when your device arrives. It is likely that the store has a few experiences loaded onto the headsets for you to try, and you can even request them to download apps or games that you look forward to using on the device during your visit.

Alternatively, you can head over to a friend who has a VR headset and give it a shot there before making your buying decision. Certain games and apps require a wide field of vision and might not work out for you. However, the rest should work equally well with a narrowed field and let you explore the virtual world with ease.

An important point to note is that most VR app stores have in place refund policies for apps and games used for less than two hours. This means that even for new purchases in the future if your experience is sub-optimal, you can simply return your purchase and look for something that is more suited to your needs.

If your requirement is really unique and specific, you could even get in touch with the developers, who might be happy to make little tweaks available in their upcoming updates to improve user experience. Do remember the VR industry is still in its infancy, and developers are keen to meet users' needs. Many might be more than happy to accommodate special needs if that opens up a new market for them.