Virtual Reality (VR) – defined as three-dimensional, stereoscopic, interactive computer graphics – is a computer-generated environment that can simulate physical presence in virtual worlds by engaging human sensory experiences. In health research, VR has been demonstrated as a successful method for mitigating pain in numerous small research studies . The VR simulation, typically designed as a game, helps distract patients from their physical pain and thereby reduces their perceived pain, and in some cases related anxiety. To make the distraction effective, it is thought that the more immersive an experience the patients have, the more distracted they will be from their pain [3, 4]. Moreover, researchers in a study by Hoffman et al.  found that the more sophisticated the VR technology, the greater the reported level of pain mitigation. Although the researchers admitted confounding variables, no other comparisons of HMDs for pain distraction had existed. Their assumption is nevertheless important, particularly because Cardboard VR does not merely present lower resolution or a smaller field of view than the Oculus Rift, but achieves VR through a fundamentally different technological approach.
Studies of the use of VR as acute pain distraction initially involved burn injuries among veterans. SnowWorld , for example, was a desktop VR simulation developed by Hunter Hoffman et al. As the researchers described it, the VE drew patients’ attention away from their pain experience and redirected it into the immersive 3D environment. Others, such as Steele et al. , used an HMD with a tracking device that controlled the movement of the gun inside 3D game. In a study of two adults undergoing painful dental procedures, Hoffman, Garcia-Palacios, et al.  demonstrated that an immersive VE resulted in lower subjective pain ratings during painful dental procedures than watching a movie without VR technology. Carlin et al.  also found that immersive VR distraction using SpiderWorld resulted in lower subjective pain ratings in two adolescents undergoing wound care for severe burns, compared to trials in which they played Mario Kart or Wave Race on a Nintendo without VR. More recently, VR combined with biofeedback and mindfulness-based stress reduction (MBSR), proved effective in reducing pain over short periods .
However, all of the VR simulations in these examples were based on older desktop platforms and traditional head-mounted displays that required professional technical operations and expensive VR equipment in medical settings. Considering the relative expense of HMDs, these factors together make VR inaccessible for patients’ everyday interactions and varying needs. Compared to higher-end VR devices like the Oculus Rift, Google’s Cardboard VR, which is cut out of pieces of cardboard and folded into a 3D viewer for smartphones, is significantly less expensive.
Given that VR pain distraction is an effective non-pharmacological analgesic, and Cardboard VR is more accessible because of its affordability and ease of use, it has the potential to act as a means to more accessible pain management which patients will be able to use themselves. Therefore, in order to discover if and to what degree Cardboard viewers may be effective for pain management, it is important to study the level of immersion that the Cardboard is capable of, compared to a traditional HMD. To this end, a research study was designed to compare immersion in three displays: a Cardboard VR, a desktop display, and a “traditional” HMD – an Oculus Rift. Because of its hardware limitations, the Cardboard VR was not expected to perform better in any way than the Oculus Rift. However, the Cardboard was predicted to provide a significantly better sense of immersion than the desktop display, despite its smaller size as a handheld device that relies on a user’s smartphone. A comparatively higher level of immersion would suggest that Cardboard has the potential to become a VR self pain-management tool that many chronic pain patients could easily access. In the following sections, the method of measuring immersion, design of the study and results are described. Findings of studies such as the one reported in this paper may prove beneficial in designing more effective and immersive experiences on mobile VR platforms, particularly for patients who need to manage their on-going, long-term pain.