Smartphones and Temporary Vision Loss: Know the Facts

We’ve all heard of how injuries or other health conditions can cause vision problems. But a recent story out of the United Kingdom shared a new, unexpected cause of transient, or temporary, vision loss: a very specific type of smartphone use.

One-eyed reading creates concern 

According to a published paper in the New England Journal of Medicine, two cases of visual loss in one eye after viewing a smartphone screen were detailed. Both individuals sought medical attention. They reported having little or no vision in one eye, while the other eye was seeing properly. What was the cause?

“Both women had been looking at their phones while in bed, with one eye on the screen, and the other covered by a pillow or blanket,” explains Dr. Joshua Pasol, a neuro-ophthalmologist at the Bascom Palmer Eye Institute, part of the University of Miami Health System. “When they took the pillow or blanket away from the covered eye, each woman was able to see clearly with that eye. However, the eye that was looking at the lit screen could not see as well.”

Eye partnership disrupted 

Dr. Pasol says that this is a normal response of the retina when exposed to light. The technical name for the temporary condition is called hyperpolarization or retinal bleaching. It’s a normal response to light exposure.

“Our retinas typically adjust to the light they are exposed to,” explains Dr. Pasol. “But our eyes are accustomed to being exposed to the same amount of light in the environment. In these published cases, the individuals did not realize they were each using only one eye to look at a smartphone screen. They were receiving more light in that eye. When a smartphone screen is turned off, and one looks away, that eye needs to re-adapt to the ambient light. Objects viewed with the eye that was focused on the lit screen will thus appear dark until this occurs. This phenomenon is fully reversible.”

In the cases described in the Journal story, once the women’s doctors obtained their histories, looked at symptom onset, and performed physical exams and testing, they found no ocular concerns. Each of the two patients regained full sight after the retinal readjustment to the ambient lighting.

Preventing transient smartphone visual loss 

If you don’t want to experience sudden transient smartphone vision loss, tips include:

  • When viewing your screen in the dark, use both eyes to prevent asymmetric (different in each eye) exposure to the lit screen.
  • View your phone in a well-lit room to avoid eye strain.
  • Wear glasses prescribed by your eye care provider.
  • Remember to use the 20-20-20 rule. “If you are staring at any screen for a long period, take a break every 20 minutes. Look at a distance about 20 feet away for at least 20 seconds. This gives your eyes a needed rest,” says Dr. Pasol.

A sudden onset of visual loss may be temporary or may result in a permanent impairment. In either case, a complete ophthalmic exam should be performed to determine the cause of the symptoms. Some causes include carotid artery disease, retinal or optic nerve ischemia, retinal vein blockages or retinal detachments.

If you suffer a change in your vision, please consult your eye care provider. Call Bascom Palmer Eye Institute toll-free at 888-845-0002 to schedule an appointment at any of its five locations.