Virtual reality headsets work with various sensors and tracking devices to create an immersive experience. For instance, the Apple Vision Pro has 5 sensors and 12 cameras — out of which four are eye-tracking cameras. Thus, making the headset heavily rely on multiple devices and systems to work well.
Eye tracking technology is an incredibly important part of virtual experiences. In this blog post, we will explore how this technology is used in VR.
What is Eye Tracking in VR?
Eye tracking in VR typically involves cameras and lights arranged in a ring format between the user and the display. It works with complex machine learning algorithms that analyze the cameras to gain real-time eye tracking data. This includes data such as pupil size, gaze direction, and eye openness.
All this eye tracking data is then used to identify a person’s response to a stimulus, such as reactions to a scene. Moreover, non-verbal cues such as pupil focus and emotional expressions enable the headset to adjust the VR experience as per your needs. For example, the headset may automatically reduce the strain on your eyes.
Read a detailed guide on Virtual Reality
6 Types of Eye Movements Used For VR Eye Tracking
The eye moves in six ways, and these movements are crucial for the VR headset to create an intuitive experience. Let’s have a detailed look at each of these eye movement types:
- Saccades: Quick eye movements of the fovea, a part which helps create great visual detail. These movements help the eye fixate on details as it moves from one object to another.
- Smooth Pursuit: Slow rotation of the eye that helps track moving objects to reduce the perceived motion blur of the objects. In simple words, it helps with image stabilization.
- Vestibulo-ocular Reflex: This involuntary reflex motion of the eyes maintains focus on objects when the head is angling back and forth. In VR, it is important for image stabilization.
- Optokinetic Reflex: This motion occurs when an object moves by at a fast pace, allowing the eyes to focus on particular features of the object. Using this reflex, the eyes move back and forth to track the details of a moving object.
- Vergence: The movement enables the eyes to create a single image of an object they both focus on. This helps give a sense of the distance between you and an object.
- Microsaccades: These are complex, involuntary eye movements that help you focus on particular objects and improve perception.
All these movements help eye tracking cameras understand a user’s gaze. Thus, they’re extremely crucial for VR eye tracking.
How Does VR Eye Tracking Work?
VR eye tracking technology is based on various eye movements. It works by understanding these movements and sending data to VR applications.
Currently, there are three methods used for VR eye tracking:
- Electro-oculography (EOG)
- Scleral search coils
- Video oculography (VOG)
Electro-oculography (EOG)
Electro-oculography uses electrodes placed into contact areas where the VR headset touches the face. Its main function measures the voltage across the positively charged cornea to the negatively charged retina.
The VR software then generates a map of the eye’s orientation using these measures of positive and negative charges. Although this method isn’t highly precise, it is the only way to measure the eyes while they’re closed.
Scleral search coils
The scleral search coils method uses a contact with a wire loop embedded in it. Electric currents move through these coils as the eyes move, reading their vertical, horizontal, and rotational movements.
This method offers a high level of accuracy. While it’s highly effective, the scleral search coils method is difficult to use in a VR headset and thus, it isn’t considered.
Video oculography (VOG)
The most common eye tracking method used by VR headsets is video oculography. This method uses images captured by cameras of the headset. The quality of these images plays an important role here.
Once captured, VOG transmits an analysis of each image to the VR headset by locating the position of the pupil and other eye features. The way the cameras are mounted to the headset determine the accuracy of the tracking.
What is VR Eye Tracking Used For?
It’s clear that VR eye tracking technology is extremely important to create realistically immersive experiences for users. However, the technology has a role for other uses as well. Let’s learn why eye tracking in VR is crucial:
1. Realistic Visuals
The information from VR eye tracking technology can help carry out a process known as “foveated rendering”. Due to this, only the elements of the virtual environment that are looked at are rendered. Thus, reducing the processing power required and creating a realistically-close, immersive environment.
As our peripheral vision is blurred in virtual reality, this also helps create a realistic sense of depth. Thus, making the image viewed feel realistic.
2. Adaptive VR Experiences
The VR eye tracking technology significantly enhances the immersion of adaptive virtual experiences. Since it allows the users to experience the virtual world intuitively, it creates a natural environment.
The eye tracking technology follows the user’s gaze to dynamically adjust the content based on where the user is looking. Thus, creating a personalized experience in real-time, based on the user’s focus and attention. For example, in virtual gaming, eye tracking allows for more realistic character interactions and AI responses.
In addition to this, eye tracking enhances VR comfort. By optimizing graphics rendering based on the user’s gaze, it helps the headset have a smoother performance and decreased likelihood of motion sickness. Hence, it not only enhances user experience but also allows a broader audience to try virtual reality.
3. Gaze-based Data
Gaze-based analytics in VR helps understand user behavior and interaction with virtual tools. These analytics take factors like a user’s gaze direction and time within a virtual environment into account to gain insights for further optimization.
Developers and researchers use this data to optimize user interfaces, find engagement levels, and understand a user’s cognitive processes in therapeutic settings. This data can also help with adaptive content delivery for a personalized experience. Thus, making gaze-based data exceptionally crucial for VR enhancement.
Learn more: What is Spatial Computing? How Does it work?
Applications of VR Eye Tracking
While virtual reality has a wide range of real-world applications, VR eye tracking can be specifically used in certain industries. These include the marketing, healthcare, and education industries.
Marketing
VR eye tracking can assist in consumer experience research by tracking where the viewer’s eyes go during the pre-purchase, purchase, and post-purchase stages. It helps understand how advertisements work on the consumer, considering AR and VR are the primary advertisement mediums.
There are also statistics that show virtual advertisements having a better engagement rate than traditional billboards. VR eye tracking can provide insight on how customers interact with products and where their eyes gravitate. Thus, helping brands design their products’ branding better.
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Healthcare
In the healthcare industry, VR eye tracking is applications in diagnostic, therapeutic, and interactive areas. For instance, the technology can diagnose certain neurological diseases by identifying any abnormal eye movements.
Another use case of the eye tracking technology is in therapeutic settings. During VR exposure therapy, the technology can help see how the patient’s gaze responds to certain triggers. Thus, changing the way exposure therapy works.
You may also read:- Virtual Reality Therapy: How Helpful and Effective Is It Really?
Education
Similar to how the eye tracking technology works in marketing, it can be used in the education industry. VR eye tracking can determine a learner’s experience through temporal and spatial movements. It could be helpful to perceive learner engagement, however, it is still new and requires more research for accurate data.
Limitations of VR Eye Tracking
As much as the eye tracking technology is important to VR, implementing it has its own drawbacks. Here are the three main challenges of VR eye tracking:
1. Data and Security Concerns
VR eye tracking collects various types of data that challenges a user’s security. Eye tracking data contains a range of personal information from cognitive states, information about mental illness or disorders, personality traits, and other sensitive data. This data also includes a user’s age, ethnicity, drug usage, emotions, and fears.
Additionally, eye tracking can reveal iris patterns of a person. Iris patterns can be used to biometrically identify someone, which leads to further concerns of identity theft for the infrared (IR) images produced by eye tracking systems.
Due to the personal information that can be found using eye tracking data, it raises cyber safety concerns for VR users. Moreover, methods to degrade or delete this information are still under research.
2. Technological Limitations
VR eye tracking technology also has its own limitations, including the quality of eye tracking data. Four of these limitations are spatial precision, spatial accuracy, high latency, and low sampling rates — all of which affect a user’s VR experience.
3. Eye Safety
Video oculography eye tracking method uses IR light to produce the contrast necessary for eye tracking. Exposure to this light for lengthy periods of time can damage the eyes’ cornea, iris, and pupil. Therefore, further research is required into this prolonged exposure as the technology is adapted by more users.
Conclusion
VR eye tracking technology is a crucial part of virtual reality headsets that helps create all the user experiences. In addition, it is helpful for developers and researchers to improve VR headsets and their interfaces with new technology. Thus, making eye tracking the forefront of new developments.
