At SIGGRAPH 2025, I had the opportunity to experience Tiramisu, a research prototype developed by Meta that boasts extraordinary features such as beyond-retinal resolution, impressive brightness, and high contrast, all while maintaining a limited field of view. Over the past decade, the evolution of affordable virtual reality (VR) headsets has been remarkable. The resolution has significantly improved from just 6 pixels per degree (PPD), which is considered legally blind, to 25 PPD for budget options, and up to 35 PPD for premium models. The Varjo XR-4 even reaches an impressive 51 PPD at its center. However, this raises important questions about how high the angular resolution needs to be for a truly lifelike experience and whether other specifications of a display system play an equally crucial role.
### Meta’s Vision for Headsets to Pass the ‘Visual Turing Test’
Meta’s leadership is focused on developing VR headsets that are so advanced that users cannot differentiate between real and virtual environments. This ambitious goal was articulated by Michael Abrash, Meta’s Chief Scientist, during a recent discussion with CEO Mark Zuckerberg and other company executives. Achieving a headset that passes the “Visual Turing Test” means users would be unable to discern if they are viewing through augmented reality (AR) goggles or wearing a VR headset.
### Understanding “Retinal” Resolution in XR
In the realm of extended reality (XR), there’s a prevailing belief that the human eye can discern up to 60 PPD. Meta’s blog regarding Tiramisu also echoes this widely accepted idea. However, many experts within Meta have expressed skepticism about this limitation since the inception of Oculus. In 2022, the company introduced Butterscotch, a prototype with a remarkable 55 PPD resolution. Although its field of view was restricted to just 50 degrees, the primary objective was to experiment with what constitutes “retinal” resolution and to identify the point of diminishing returns through real-time resolution adjustments.
During SIGGRAPH 2023, I was able to try an advanced version of Butterscotch named Butterscotch Varifocal. This model combined “retinal” resolution with varifocal capabilities, resulting in an immersive experience devoid of pixelation or aliasing. While the theoretical benchmark of 60 PPD aligns with 20/20 vision, the actual scenario is far more nuanced.
### The Technicalities of Pixel Delivery in VR
The way pixels are sampled and displayed in a VR headset is notably different from a standard flat monitor. VR systems craft a virtual environment, sampling from the user’s exact viewpoint. This means that techniques used for flat screens, which align edges of text to minimize pixel splitting, cannot be applied. Furthermore, VR images are intentionally barrel-distorted to counteract the pincushion distortion caused by the lenses necessary for a wide field of view. Consequently, there is no straightforward one-to-one correspondence of pixels from rendering to visual perception. Additionally, around 30% of individuals have vision that exceeds 20/20, suggesting that even without the sampling complications, 60 PPD might not represent the upper limit for everyone.
To validate the skepticism surrounding the 60 PPD benchmark and incorporate insights from their previous research on the importance of brightness and contrast, Meta’s Optics, Photonics, and Light Systems (OPALS) team developed Tiramisu.
### Tiramisu: A Leap Towards the Visual Turing Test
Tiramisu features an angular resolution of 90 PPD, a brightness level of 1400 nits, and a contrast ratio three times that of the Quest 3. Utilizing micro-OLED displays similar to those found in headsets like Bigscreen Beyond 2, Tiramisu achieves its impressive 90 PPD by magnifying these displays over a limited field of view of only 33°×33°. Unlike other micro-OLED headsets that have employed pancake lenses, Tiramisu utilizes a custom refractive lens.
Recent advancements in pancake lenses have made headsets thinner and sharper, but they also suffer from poor optical efficiency, resulting in significant light loss and diminished brightness perceived by the user. While future display innovations may address this issue, current models like Quest 3 and Apple Vision Pro can only deliver about 100 nits to the viewer’s eyes, a stark contrast to typical laptop displays that achieve around 200 nits and high-end HDR TVs that exceed 1000 nits.
Tiramisu’s unique lens design comprises three elements crafted from high refractive index flint glass, which Meta claims corrects nearly all geometric and chromatic aberrations. Each element features anti-reflective coatings that enhance contrast and maximize brightness across the field of view.
### Visual Quality and Immersion with Tiramisu
During my hands-on experience, I found Tiramisu to be notably heavy and thick, requiring me to support it without a head strap. Nevertheless, its remarkable resolving power allows for an impressive 90 PPD and enables a substantial amount of light to reach the viewer compared to any existing pancake optic. Meta showcased various scenes rendered with Unreal Engine 5, powered by a high-performance desktop PC and Nvidia’s DLSS 3, with a highlight being the Electric Dreams park sample that featured photorealistic details through advanced technologies.
The visual quality presented by Tiramisu was striking, showcasing vibrant and richly detailed images without any visible distortions. In the park scene, even the smallest details appeared impeccably smooth, devoid of pixelation. Similarly, in an aircraft cockpit setting at night, I could discern the intricate textures of small switches, as well as distant runway markers.
While I could not directly compare Tiramisu to its predecessor Butterscotch, Meta’s researchers noted a clear distinction between the two, particularly in angular resolution. However, what truly stood out was Tiramisu’s brightness and contrast.
### Starburst: A Breakthrough in High-Dynamic Range Display Technology
Is high-dynamic range (HDR) the essential feature for next-generation VR displays? Insights gained from Meta’s latest demonstrations and discussions with the head of display systems research indicate that HDR will play a critical role. My previous experience with Meta’s Starburst prototype at SIGGRAPH 2022, which boasted a staggering 20,000 nits, reinforced my belief that brightness is a crucial yet often overlooked specification in VR displays.
In Tiramisu, the LED lights depicted in the aircraft cockpit and runway appeared convincingly lifelike, contrasting sharply with the dimmer representations in the Quest 3. This striking realism, enhanced by the high brightness and contrast, significantly improved the sense of depth, even without the varifocal capabilities present in some headsets. This phenomenon, although poorly understood, has also been observed in HDR TVs.
Moreover, Tiramisu’s vivid and bright imagery was a pleasure to behold. As Douglas Lanman, head of DSR, noted, the experience was akin to seeing a 4K HDR OLED TV for the first time, but even more impressive.
### Tiramisu 2: The Quest for Practicality
Unlike Boba 3, which Meta could potentially bring to market, Tiramisu’s design presents significant challenges. Its limited field of view and substantial weight would make it uncomfortable for prolonged use. At SIGGRAPH, Meta showcased the lens design for a forthcoming headset referred to as Tiramisu 2.
Tiramisu 2 aims to strike a balance between angular resolution, brightness, and contrast, along with field of view and comfort. While the original Tiramisu has a refractive lens stack measuring 63mm in thickness, Tiramisu 2 plans to integrate refractive and diffractive elements, reducing thickness to approximately 26mm—just slightly thicker than the Quest 3’s 23mm. This model is expected to provide a horizontal field of view of about 90 degrees, similar to what was offered by the original Oculus Rift.
Although Tiramisu 2 will compromise slightly on angular resolution and brightness, targeting 60 PPD and 700 nits, these numbers still represent a substantial improvement over the Quest 3, offering more than double the angular resolution and seven times the brightness. These seem like reasonable trade-offs for a more practical headset.
As for whether Tiramisu 2 will make an appearance at SIGGRAPH 2026, Ying Geng, Tiramisu’s lead, did not provide any confirmation. While the future remains uncertain, I remain hopeful that witnessing an image even half as realistic as Tiramisu across a 90-degree field of view will significantly reshape my understanding of what specifications are vital for the next generation of shipping VR display systems.
### Boba 3: The Ultra-Wide Experience
At SIGGRAPH 2025, I also engaged with another Meta prototype headset, dubbed Boba 3, developed by the DSR team. Although Boba 3 shares similar angular resolution and low brightness and contrast levels with headsets like the Quest 3, it immerses users in a vast 180° horizontal by 120° vertical field of view.
My hands-on experience with Boba 3 has left me more optimistic than ever about the future of virtual reality.
