Virtual reality appears safe for the eyes

In a new paper from the Myopia Lab, Philip Turnbull and John Phillips report that 40 minutes of virtual reality headset wear doesn't appear to have a significant effect on the eyes - especially the binocular vision system. In the real world, as objects move closer, the eyes will converge to keep the image single, and the eye will 'accommodate', or change its focal length, to keep it in sharp focus. VR headsets cause a disconnect between the fusional system and focussing system of the eye, as while the eyes need to converge to 'fuse' the 3D images in the headset, the screen remains at the same distance, so no change in focus is required. 

The illusion of depth in virtual reality headset is created by offsetting items the screen for each eye. The nearer the object, the greater the offset, and the more the eyes need to converge in order to keep the object single. However, unlike the real world, this must be done without changing the focus of the eye - creating a conflict between the two systems. 

Example of the outdoor (real) environments, and the equivalent virtual reality worlds. 

The experiment placed participants into four different environment - two real, two virtual - two outdoor, two indoor. They took a range of measures of the visual system, including how well the eyes focus, how well they work together, and how stable the fusion is, before and after spending 40 minutes in one of the environments. The changes in the measure was then compared between the four different environments. 

While there was no major effect on the binocular system, in an unexpected finding, they found that the choroid, a vascular layer which supplies parts of the retina with blood, increases in thickness following headset wear, but not when conducting the same activity in the real world (e.g. walking outside, or using a computer). This suggests that the use of virtual reality headsets is not bad for the eyes, and if the choroidal findings have a similar mechanism to those seen when preventing myopia, virtual reality may even be beneficial to the eyes

You can find the full paper (Free, Open Access, doi:10.1038/s41598-017-16320-6) at Scientific Reports