Eye tracking

Eye tracking is the process of assessing how the eye moves when it looks at something. The phrase also describes technology that mimics or predicts how the eye moves. Eye tracking technology may be invasive or noninvasive. Originally developed to assist disabled people, eye tracking technology has progressed to the point that it has applications in business, entertainment, medicine, advertising, and other fields.

Background

The eye works by capturing rays of light, which enter through the cornea at the front of the eye, in nerve endings on the retina, which is located in the back of the eye. These nerve endings convert captured light into nerve impulses, which travel to the brain along the optic nerve. The brain interprets those impulses into the sense known as sight.

Even though all of this happens in a fraction of a second, by the time the brain has interpreted what the eye has seen, the eye is already seeing something else. The brain compensates for this by predicting where the eye will look next. It provides information about this prediction along with the actual image the eye sees. This is why baseball players can hit a moving fastball and drivers can react to avoid a swerving car.

Eye tracking technology attempts to capture data related to both of these functions: it tracks where a person has looked and anticipates where a person will look. Depending on the intended use of the technology, it may capture information about what a person sees, enhance what is seen, or use information about what a person is seeing to control a device, such as a computer, a vehicle, or surgical equipment.

Overview

Eye tracking technology works by capturing data from the eyes on special sensors, which are customized for the particular situation in which they will be used. The tracking device then uses special computer algorithms to interpret the data that have been gathered in much the same way that the brain interprets the nerve impulses generated by the light rays the eye gathers. These algorithms create data that various applications or devices can use to respond to what the person sees.

The technology was first considered as a way to help those who have physical disabilities. It enables people with physical or neurological disabilities that affect their hands to control electronic devices. For instance, if a disabled person wants to operate a computer, a specially equipped monitor will use a projector to shine infrared light beams in and near the person's eyes. Infrared light is invisible to the human eye, but it enables special cameras in the monitor to capture images of the eye. The light rays create reflections on the cornea of the eye, which can be captured and tracked by the monitoring system. From these reflections, the system can determine how the eye is moving—such as how open the pupil is (which determines how much light is entering the eye) and how the eye is positioned. This information is interpreted using algorithms to calculate where on the computer the person is looking. By gazing at various parts of the screen, the person can direct the computer to perform functions that are usually done with the aid of the computer's mouse and keys.

Variations of this tracking technology can be used in other applications. Advertisers can use eye tracking technology to determine what people look at on a monitor and which areas hold their interest the most or least. The data gathered can help advertisers design more informative and relevant ads and use them more strategically for greater impact. Researchers may use eye tracking technology to study human behavior. For example, they may try to determine what people see first in a new place, how people identify familiar faces in a crowd, or how people respond to certain types of stimuli, such as colors, lights, and store displays. Researchers hope that tracking how people look at and see things can help them determine how children learn to make sense of their environments. They also hope to learn how various visual stimuli affect children with autism and people with sensory processing issues or neurological conditions. Tests have also been developed to allow physicians to use eye tracking to test and diagnose some of these conditions.

Eye tracking technology can be used to control many types of equipment. Devices with eye tracking technology can alert drivers who have dozed off or who are not paying sufficient attention to the road. The entertainment and gaming industries have great interest in the potential for eye tracking technology to create better, more immersive experiences for those watching movies or playing video games.

Experts have claimed that eye tracking technology can interact with nearly anything that a person can look at or see. They have developed two main types of technology: one type is integrated with the eye, and the other is part of a device. The integrated technology uses a type of film or lens that attaches to the cornea. The film or lens has small sensors that react to eye movements and to a device called an electromechanical transducer that can react to electromagnetic fields or light to help track the eye's movement. For most uses, however, eye tracking technology is incorporated into a device, such as special glasses or goggles or a monitor that shines infrared or near-infrared light into the eyes and tracks the reflections.

The field of eye tracking is advancing rapidly. Researchers have created or are working on applications for everything from household use to deep-sea and space exploration. The technology has been incorporated into technologies such as e-readers, cell phones, television remotes, home entertainment and video gaming equipment, devices to help disabled people, and equipment to help control unmanned drones and missiles. Researchers have also begun integrating artificial intelligence (AI) into eye tracking technology, making it more powerful and efficient. For instance, AI algorithms are used to analyze eye movements and predict decision-making behaviors, an application that can provide insight into a variety of fields, from marketing to medical diagnostics. Such advances are seen as crucial to future developments, and technology giants like Meta and Google have worked to acquire eye-tracking companies to take better advantage of the technology.

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