Health Excessive smartphone use: Japan’s surge in esotropia

The SCMP reported that a growing number of people in Japan are being diagnosed with a condition where the eyes turn inward, giving the appearance of being cross-eyed—an issue that medical experts are increasingly linking to the excessive and improper use of smartphones. "Acquired esotropia" is a form of strabismus (斜視 Shashi), in which one eye turns toward the nose while the other remains forward-facing, resulting in misalignment.

It is particularly common among younger Japanese, many of whom experience symptoms such as double vision and reduced depth perception. Health professionals warn that prolonged use of digital screens—especially when held too close to the face or used while lying down—may contribute significantly to the onset of this condition.

According to a Kyoto University study published in June last year, roughly one in 50 people in Japan suffers from strabismus. The more common form involves one eye turning outward, but cases of inward-turning eyes have noticeably increased in recent years. A further study carried out by the Japanese Association for Strabismus and Amblyopia, along with the Japanese Association of Pediatric Ophthalmology, examined nearly 200 patients with sudden-onset strabismus. The research tracked the effects of proper digital device use over three months, aiming to understand better whether adjusting usage habits could help alleviate the symptoms.

Even after these patients kept their devices at least 30cm (12 inches) away from their eyes and took five-minute breaks every 30 minutes, 56 per cent of them either did not experience any change or their symptoms worsened, found the study published in the Japanese Journal of Ophthalmology in March this year. [...] Among the patients, just 13% did not use their devices excessively. The highest proportion of patients with the condition were middle and high school students, with the most common age being 16. While acquired esotropia is treatable if caught early, it may be difficult to correct down the line, health experts have warned.

Click to expand...

Really? People never read books for hours on end before handheld devices came along?

Amblyopia ('blunted vision') is a very interesting condition; if the eyes are misaligned during the critical period of the development of the visual cortex (up to about 11 years old) the 'wiring' from the eye to lateral geniculate nucleus to primary visual cortex doesn't develop properly and vision is impaired in the absence of a refractory issue. I have slight amblyopia in my left eye as a slight esophoria wasn't picked up during my formative years. It's rather like pixels are missing from the vision in my left eye but the edges of the missing areas are merged to the normal areas. Fascinating!

Like being pigeon-toed or having yaeba (八重歯), esophoria will no doubt be regarded as 'cute' in the future.

I think in years to come, smart devices and in particular, social media, will be found to be dangerous to health as cigarettes were found to be to…well…everything!

The late, great Marty Feldman clearly didn't spend too much time on his device.

Ukigumo said:

The late, great Marty Feldman clearly didn't spend too much time on his device.

Click to expand...

One of my all-time favourites (Young Frankenstein)! Clearly, he ogled girls left and right.

thomas said:

One of my all-time favourites (Young Frankenstein)! Clearly, he ogled girls left and right.

Click to expand...

I ordered a copy of it just yesterday!

thomas said:

One of my all-time favourites (Young Frankenstein)! Clearly, he ogled girls left and right.

Click to expand...

Frankenstein: Igor, help me with these bags.
Igor: Ok, you take the blonde, I'll take the one with the turban.