A 30-year-old woman Manju (name changed to protect privacy) had vision problems for one and half years. Symptoms were of seeing floaters, flashes of lights, dark zigzag lines and episodes of blurred vision, which recurred several times in the day. They would last for seconds to minutes and repeat every 10-15 minutes. In addition, she would go totally blind for a few minutes at nights (on waking up in middle of night to use washroom).

She initially consulted an ophthalmologist who after a detailed eye check-up ruled out any eye disease. She was then referred to me to rule out any neurological cause for her vision-related symptoms. Detailed clinical neurological examination was normal and moreover, her symptoms did not point to any specific brain nerve related disease. So, I took a detailed history. She revealed that she had quit her job as a beautician one and a half years ago to look after her specially abled son. From the same time, she had started spending too much time on smartphone. She would look at the smartphone screen for 8-10 hours during day and 2 hours at nights in darkness (with lights switched off).

Dr Sudhir Kumar, Senior Consultant Neurologist, Apollo Hospitals, Jubilee Hills, Hyderabad; suspected that her vision symptoms were related to looking at smartphone screen for long hours (as I had seen similar cases in the past too). I did not order any investigations neither did I start her on any medicines. I counselled her and advised her to restrict usage of smartphone. She agreed to reduce the time spent watching the screen of her smartphone. She returned for review after a month and to our pleasant surprise, all her vision-related problems had subsided. She reported that her vision was normal. This confirmed our suspicion of her being a case of “smartphone vision syndrome”.

There could be multiple mechanisms to explain the vision-related problems with excessive smartphone use.

• Muscles involved in moving the eyeballs and for eyes to focus may get fatigued or weakened with excessive use. This can adversely affect the clarity of vision and may cause double vision at times.
• Digital screens generate heat. In addition, people blink their eyes less frequently while watching a digital screen. Both these can increase the chances of dry eyes, leading to blurring of vision and other eye-related symptoms.
• Many people who are addicted to smartphones don’t get adequate sleep, and sleep deprivation is known to increase the eye strain and visual problems.
• Short duration blindness in one eye may occur after using smartphone at night during darkness. The prevailing hypothesis is that while in the lateral recumbent position (with head resting on one palm), one eye is blocked (such as with a pillow, bed sheets) and subsequently becomes dark-adapted while the other eye exposed to the bright screen of the device becomes light-adapted. After the screen of the device is deactivated and the room is once again lit with low ambient light, the light-adapted eye is perceived to have poor or no vision. The vision returns to the patient’s baseline after several minutes.

In today’s digital era, where digital screens are inescapable, how should one prevent such a situation?

• Completely avoiding digital screen is impossible as it is not only the leisure and entertainment related stuff but most of the work and studies too happen over digital screens. So, one can look towards reducing the time spent watching the digital screens.
• Watching the screen time beyond work or studies should be reduced.
• One should maintain adequate distance from the screen (avoid being too close to the screen),
• Avoid watching the smartphone screen in darkness.
• Follow the 20-20-20 rule: take a break every 20 minutes to look at something 20 feet away for 20 seconds.
• In any vision-related symptoms are noted, one should consult a doctor for proper diagnosis and treatment.