Late night smartphone use makes women go blind

Taking your smartphone to bed won’t just leave you tossing and turning, it can actually make you go temporarily blind, a team of London-based doctors have warned.

A letter to the New England Journal of Medicine from a London-based team of researchers and medics details two cases of “transient monocular vision loss” the team said occurred in women who habitually took their smartphones to bed before tapping away through the night.

In the first case, a 22-year-old woman “presented with a several months’ history of recurrent impaired vision in the right eye that occurred at night”. In the second, “a 40-year-old woman who presented with a six-month history of recurrent monocular visual impairment on waking, lasting up to 15 minutes.”

The docs ran their standard battery of ophthalmic and cardiovascular tests, but all appeared normal.

However, “When the patients were seen in our neuro-ophthalmic clinic, detailed history taking revealed that symptoms occurred only after several minutes of viewing a smartphone screen, in the dark, while lying in bed (before going to sleep in the first case and after waking in the second)."

Consequently, "Both patients were asked to experiment and record their symptoms. They reported that the symptoms were always in the eye contralateral to the side on which the patient was lying. “

The team hyphothesized that the symptoms were down to “differential bleaching of photopigment”, with one become light adapted to the screen, while the other eye was blocked, by their pillow for example. Or, put simply, the women were staring at their mobes with one eye. When both eyes were exposed to normal darkness, the light-adapted one was “perceived to be blind” for several minutes.

After getting approval from the appropriate ethics committee, a pair of the authors subjected themselves to similar viewing patterns to test the effects of monocular smartphone viewing, presumably under lab conditions. The results seemed to bear out their theory.

As the team note, smartphones are being used round the clock, and vendors are making screens ever brighter. “Hence, presentations such as we describe are likely to become more frequent.”

Crucially, they suggest, “Our cases show that detailed history taking and an understanding of retinal physiology can reassure both patient and doctor and can avoid unnecessary anxiety and costly investigations.”

You can read the full report here, but please, use both eyes. ®