According to a study published in IEEE Transactions on Biomedical Engineering, augmented reality (AR) devices like Microsoft’s HoloLens have an important obstacle to overcome for their users – the natural mechanics in which our eyes focus on objects.

The IEEE study, conducted by researchers from the University of Pisa, explored how focal rivalry affected participants’ performance on tasks that take place within two meters of the eye. The researchers asked 20 participants to take a “connect-the-dots” test, once using their unaided vision and once using the HoloLens, where a sequence of numbered dots was visually projected using an optical see-through (OST) device mounted on participants’ heads. Computer-generated content is projected onto semi-transparent displays in front of the user’s eyes, and the user can still see real-world objects beyond the screen.

A series of experiments tested how augmented reality (AR) affects participants’ ability to simultaneously focus on real-world objects (the paper and a pen) and a "connect-the-dots" task projected in front of their eyes via a Microsoft HoloLens.
A series of experiments tested how augmented reality (AR) affects participants’ ability to simultaneously focus on real-world objects (the paper and a pen) and a “connect-the-dots” task projected in front of their eyes via a Microsoft HoloLens. Image courtesy of IEEE.

After completing the test, participants reported that their performance was similar whether they used the HoloLens or not. However, the qualitative data showed that, on average, participants made errors of 2.3 mm in length when using the HoloLens (with a maximum error of 5.9 mm), compared to errors averaging 0.9 mm during the naked eye tasks.

These images simulate the focal rivalry problem that users experience when they wear AR headsets. In the image on the left, the camera is focused on the ruler and pencil. On the right, the camera is focused on the numbers projected by the headset.
These images simulate the focal rivalry problem that users experience when they wear AR headsets. In the image on the left, the camera is focused on the ruler and pencil. On the right, the camera is focused on the numbers projected by the headset. Image courtesy of IEEE.

“Unfortunately, the users were not aware of [their] bad precision performances in AR-guided tasks,” said Marina Carbone, a researcher involved in the study. “To further evaluate this point, we are now planning to repeat the experiments acquiring the EEG during the exercise.”

As this study is reviewed and re-examined, it provides insights that AR display manufacturers like Google, Microsoft, and Lenovo should consider in their next generations of products.