Most virtual reality (VR) and augmented reality (AR) displays present virtual objects at a fixed focal distance, creating a mismatch between where the eyes converge and where they focus. Researchers tested a varifocal display that adjusts focus to match virtual-object depth. In a 3D pointing task, it significantly improved average movement speed and information throughput without significantly affecting error rates. However, benefits varied among users, highlighting the potential for more personalized AR display designs.
Augmented reality (AR) overlays digital objects on the real world, while virtual reality (VR) immerses users in computer-generated environments. In both technologies, interaction with virtual objects at different depths can be challenging when displays do not reproduce how human eyes focus. Looking at different distances requires the eyes to converge on an object and adjust focus together. Most AR and VR headsets show images at a fixed focal distance, even when virtual objects appear at different depths. This mismatch, called the vergence-accommodation conflict (VAC), may affect comfort and interaction.
Addressing this challenge, a collaborative international research project was led by Assistant Professor Xiaodan Hu from the Shibaura Institute of Technology, Japan, alongside a global team of experts from Japan, China, and Canada. The team members include Dr. Monica Perusquía-Hernández and Dr. Kiyoshi Kiyokawa from the Nara Institute of Science and Technology, Japan; Dr. Yan Zhang from Shanghai Jiaotong University, China; Dr. Mayra Donaji Barrera Machuca from the University of Calgary, Canada; Dr. Anil Ufuk Batmaz from Concordia University, Canada; and Dr. Wolfgang Stuerzlinger from Simon Fraser University, Canada. The collaboration brought together expertise in hardware development and user studies from the Asian team and interaction experiment design from the Canadian team. Their findings were published online on August 28, 2026, in the journal Virtual Reality .
The team tested whether a varifocal display, which adjusts focus to match an object's depth, could improve 3D pointing. With a stereoscopic AR prototype, participants used a tracked wand to select virtual targets of different sizes and distances. Researchers compared fixed-focal and varifocal viewing during lateral movements and movements in depth. They measured movement time, error rate, and throughput, a measure of task efficiency. The first study involved 24 participants, followed by a second study with 12 additional participants to verify the hardware's performance.
In the first study, varifocal viewing significantly reduced movement time and increased throughput. Error rates did not significantly change, indicating that faster performance did not come at the cost of accuracy. Benefits appeared greater for depth movements, although the difference by direction was only borderline significant for throughput.
"Our results show that adjusting focal distance can improve how people interact with virtual objects, beyond its effects on visual perception," says Dr. Hu. "But users do not all benefit equally, making individual differences an important question for future research." Varifocal displays could help AR and VR headsets provide more natural focusing cues when people interact with objects at different distances. However, this study did not test long-term eye health or establish that the technology prevents eyestrain. Participants' ratings showed no clear preference between display modes, and discomfort was mild.
Overall, the findings indicate that reducing VAC with varifocal technology can improve 3D pointing performance, while highlighting the need to understand why responses vary. Differences in binocular vision or depth perception may contribute, but these factors were not measured. The prototype also had a limited field-of-view and did not use eye tracking to adjust focus, limiting its resemblance to everyday AR use. "Future studies can examine which user characteristics predict greater benefits and how displays might adapt to individual needs," says Dr. Hu. This work offers a basis for evaluating personalized AR systems.
Reference
DOI: 10.1007/s10055-026-01473-5
About Shibaura Institute of Technology (SIT), Japan
Shibaura Institute of Technology (SIT) is a private university with campuses in Tokyo and Saitama. Since the establishment of its predecessor, Tokyo Higher School of Industry and Commerce, in 1927, it has maintained "learning through practice" as its philosophy in the education of engineers. SIT was the only private science and engineering university selected for the Top Global University Project sponsored by the Ministry of Education, Culture, Sports, Science and Technology and had received support from the ministry for 10 years starting from the 2014 academic year. Its motto, "Nurturing engineers who learn from society and contribute to society," reflects its mission of fostering scientists and engineers who can contribute to the sustainable growth of the world by exposing their over 9,500 students to culturally diverse environments, where they learn to cope, collaborate, and relate with fellow students from around the world.
Website: https://www.shibaura-it.ac.jp/en/
About Assistant Professor Xiaodan Hu from SIT, Japan
Dr. Xiaodan Hu is an Assistant Professor at the Shibaura Institute of Technology, Japan. She directs the Augmented Imaging and Displays (AID) Laboratory. Previously, she worked as a postdoctoral researcher at Graz University of Technology in Austria. Since April 2024, she serves as a commissioned instructor at the Nara Institute of Science and Technology, where she received her M.Sc. and Ph.D. degrees under Professor Kiyoshi Kiyokawa. Her research focuses on optical see-through head-mounted displays, vision augmentation, and human visual perception within AR. She is dedicated to designing display systems that align with human visual characteristics, ensuring comfortable experiences.
Funding Information
JSPS KAKENHI (22H00539 and 26K21776), Japan.
