The visual span, defined as the number of letters that can be accurately recognized in a single eye fixation, is a fundamental sensory constraint on reading speed. While well-studied on desktops, visual span in virtual reality (VR) remains largely unexplored, despite the increasing use of text-heavy VR applications. This gap is critical, as VR's unique constraints (e.g., limited angular resolution, optical distortions, and vergence-accommodation conflict) may fundamentally restrict text intake. We present the first empirical study to directly measure visual span in VR using the trigram paradigm and compare it to a matched desktop baseline. Although the profile shape of the visual span was similar across conditions, its size was significantly reduced in VR, averaging 4.28 letters versus 10.72 on desktop (a ≈60% reduction). These findings reveal a fundamental limitation and lay the groundwork for designing more readable and efficient text experiences in immersive environments. ... Read more