Excessive smartphone use can not only harm one’s mind but also cause physical problems. Most people are aware of text neck, the condition that refers to pain due to wrong neck posture caused by staring down at smartphone for long. Now another serious physiological hazard has been linked to excessive smartphone use, especially among children — acute internal strabismus, a condition commonly called cross-eyed in which one or both eyes look towards the nose.
Research by two Japanese medical associations has established a link between excessive smartphone use and the eye condition. Acute internal strabismus has been a rare condition but Japanese doctors have reported a sudden increase in the number of affected people of late.
Between January and February last year, the two Japanese groups surveyed 1,083 of their members, including child eye doctors, asking if they had examined patients with acute internal strabismus, aged 5 to 35, according to The Asahi Shimbun. More than 40 per cent, or 158 of the 371 doctors who responded, said they had examined patients during the year who had become cross-eyed.
“It’s quite a surprise that more than 40 percent of the eye doctors had those patients,” Miho Sato, president of the Japanese Association for Strabismus and Amblyopia and a professor of pediatric ophthalmology at Hamamatsu University Hospital told The Asahi Shimbun. Though the survey of Japanese doctors has established a clear link between the condition and excessive smartphone use, a causal relation has not been established yet.
Playing online games that can keep the player glued to the small smartphone screen for hours can also cause double vision. Sato cited the case of a 17-year school student who played games holding his phone close to his face for five to seven hours after arriving home from school. He started experiencing double vision, seeing two clocks overlapping on the wall of his classroom and an oncoming car as two. Blinking did not restore his vision to normal. He found closing his left eye eliminated one of them.
He was diagnosed with acute internal strabismus. After Uematsu quit playing online game, his double vision lessened gradually but his eyesight didn’t return to normal completely until he underwent surgery. According to Sato, some people get better if they stop using their phones. He advises at least 30-minute breaks when using smartphone for longer periods.
Of the 158 doctors who responded to the Japanese survey, 122 doctors, nearly 80 per cent, said they had treated patients who they suspected contracted the condition from using digital devices such as smartphones. Thirty-seven doctors examined patients whose symptoms improved after they stopped using the devices.
In 2016, a South Korean research found possible relationship between convergent strabismus, a symptom in which a patient’s eye moves inward eventually to become “cross-eyed”, and excessive use of smartphones based on its study on 12 patients aged seven to 16. The research team said the 12 patients’ daily use of smartphones came to four to eight hours. The distance between their eyes and screens were also close at 20 to 30 centimeters. Nine of the 12 patients, however, were cured from the disorder after ceasing to use smartphones for around two months.
In a 2018 poll by the Forum Research poll, which surveyed 1,408 Canadians voters, just over 1 in 10 (12 per cent) said they spent three hours or more on their phones. However, a quarter (26 per cent) of those aged 34 and younger said they spent the same amount of time on their phones.