Danny Bittman, who has worked as a virtual reality developer for four years, suggested it could have affected his eyesight. "Just had my first eye doctor visit in three years. Now I'm very worried about my future VR use. I have a new eye convergence problem that acts like dyslexia. The doc, a headset owner, is convinced my VR use caused this. He said "these glasses we usually prescribe to 40-year-olds", he tweeted.

He went on to describe the problem: "My eyes jump when I read things like a screen or books. I've always had a small level of this but it's greatly intensified now. It's also linked to headaches and vertigo." He said that the issue was about "prolonged use", and admitted that he could spend up to six hours a day wearing a headset, split into 30-minute sessions. Ceri Smith-Jaynes, from the Association of Optometrists, told the BBC: "We currently do not have any reliable evidence that VR headsets cause permanent deterioration in eyesight in children or adults. There have been some studies looking into the effects of short-term use of VR headsets only; these did not reveal a deterioration in eyesight. "However, some people do suffer from temporary symptoms such as nausea, dry, irritable eyes, headache or eyestrain. " But she did have some advice about usage: "If you spend all day in VR without a break, you'll need time to readjust to the light and the different visual environment of the real world. I would suggest taking a five-to-ten minute break each hour, using that time to move about, blink and look out of a window, or take a short walk.