Smartphones and Temporary Loss of Vision: 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 temporary loss of vision: a very specific type of smartphone use.
One-eyed reading creates concern
In a paper published in the New England Journal of Medicine, researchers detailed two cases of vision loss in one eye after viewing a smartphone screen. 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,” says Dr. Joshua Pasol, a neuro-ophthalmologist at the Bascom Palmer Eye Institute. “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.”
When the eye partnership is disrupted
This is a normal response of the retina when exposed to light, says Dr. Pasol. The technical name for the temporary condition is called hyperpolarization or retinal bleaching.
“Our retinas typically adjust to the light they are exposed to,” says 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. When you look at something with the eye that was focused on the lit screen, it will 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:
- Use both eyes. When viewing your screen in the dark, use both eyes to prevent asymmetric (different in each eye) exposure to the lit screen.
- Look at 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, you should ask you doctor for a complete ophthalmic exam 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 one of its convenient locations.
Nancy Moreland is a contributor for UMiami Health System.