A smartphone attachment created by engineers at the University of California, San Diego has the potential to provide low-cost, accurate neurological condition screening for individuals of any skin tone. The conditions screened for include Alzheimer’s disease and traumatic brain injury.
The technology, which is available on all smartphone models, has the potential to enhance the equity and accessibility of neurological screening procedures. It was recently published in Scientific Reports.
The attachment fits over the camera on a smartphone and enhances its ability to take precise measurements of the pupil, or the dark core of the eye, and clear video recordings. According to recent research, monitoring changes in pupil size during specific tasks can reveal important information about how a person’s nervous system works. For instance, when performing intricate cognitive tasks or reacting to sudden stimuli, the pupil typically dilates.
Pupil size tracking can be challenging for people with dark eye colors, such as those with darker skin tones, though, as traditional color cameras have trouble telling the pupil apart from the surrounding dark iris.
UC San Diego engineers added a specialized filter to their smartphone attachment to improve the pupil’s visibility by allowing only a specific range of light to enter the camera. The extreme red end of the visible spectrum, which is located right before infrared light, is known as far-red light. The dark pigment in the iris, called melanin, reflects longer wavelengths of light, including far-red light, while absorbing the majority of visible light. The iris appears noticeably lighter when far-red light is imaged in the eye while other wavelengths are blocked out, making the pupil with a regular camera.
“A significant problem in the design of medical devices that rely on optical measurements has resulted in the devices functioning well for people with light skin and eyes, but not for those with dark skin and eyes,” stated Edward Wang, the study’s senior author and an electrical and computer engineering professor at UC San Diego’s The Design Lab, where he also serves as the director of the Digital Health Technologies Lab.
Our goal is to create a future where everyone has equitable access to inexpensive, remote health care by concentrating on how to make this work for everyone while maintaining a low-tech and straightforward solution.
The fact that this technology is made to function on all smartphones is another aspect that increases accessibility. Pupil measurements have traditionally been made with infrared cameras, which are limited to expensive smartphone models. This traditional approach restricts accessibility to those who can afford more expensive smartphones because regular cameras cannot detect infrared light. This technology creates a level playing field by using far-red light, which is still within the visible spectrum and can be photographed with a standard smartphone camera.
“The problem with depending on specialized sensors, like an infrared camera, is that not all phones have it,” said Colin Barry, the study’s first author and a Ph.D. candidate in Wang’s lab studying electrical and computer engineering. “We developed a reasonable and affordable remedy to
The fact that this technology is made to function on all smartphones is another aspect that increases accessibility. Pupil measurements have traditionally been made with infrared cameras, which are limited to expensive smartphone models. This traditional approach restricts accessibility to those who can afford more expensive smartphones because regular cameras cannot detect infrared light. This technology creates a level playing field by using far-red light, which is still within the visible spectrum and can be photographed with a standard smartphone camera.
“The problem with depending on specialized sensors, like an infrared camera, is that not all phones have it,” said Colin Barry, the study’s first author and a Ph.D. candidate in Wang’s lab studying electrical and computer engineering. “We developed a reasonable and affordable remedy to
The fact that this technology is made to function on all smartphones is another aspect that increases accessibility. Pupil measurements have traditionally been made with infrared cameras, which are limited to expensive smartphone models. This traditional approach restricts accessibility to those who can afford more expensive smartphones because regular cameras cannot detect infrared light. This technology creates a level playing field by using far-red light, which is still within the visible spectrum and can be photographed with a standard smartphone camera.
“The problem with depending on specialized sensors, like an infrared camera, is that not all phones have it,” said Colin Barry, the study’s first author and a Ph.D. candidate in Wang’s lab studying electrical and computer engineering. “We developed a reasonable and affordable remedy to provide these kinds of emerging neurological screenings regardless of the smartphone price, make or model.
The attachment is used by attaching it to the smartphone camera and placing it over the user’s eye. Subsequently, the smartphone records video of the eye while administering a pupil response test through the use of a bright light flash. Pupil size is tracked by a machine learning model using the eye’s recorded video. The twelve volunteers, whose eye colors ranged from light blue to dark brown, were chosen to test the researchers’ smartphone attachment. The measurements from the smartphone were verified by comparing them with the gold standard pupillometer, which is used in the clinic to measure pupil size.
Moving forward with the technology for widespread neurological screenings in at-home settings is the next stage of this project. The researchers are trying to optimize the design for mass production in order to get it to that point. Additionally, they are improving the technology’s usability, which is especially important for senior citizens who are more likely to develop neurological disorders.