If you’ve been experiencing worsening eye problems over the last several years, you aren’t alone. An eye surgeon in the U.K. has noticed a 35 percent increase in the number of patients diagnosed with advancing myopia (short sightedness) which he believes is being cause by smartphones.

David Allamby, founder of Focus Clinics, says the increase dates back to the launch of smartphones in 1997 and unfortunately, it’s a problem that’s just now taking root. He believes the issue, dubbed screen sightedness, could increase in frequency by 50 percent over the next 10 years and half of 30-year-olds could suffer from it by 2033.

Increased smartphone usage along with time spent watching television and using computers is putting children and young people at risk of permanently damaging their vision. One of the main reasons for concern relates to a recent study which found that the average smartphone user holds their device 30cm from their face while some use it as close as 18cm. Newspapers and books, on the other hand, are typically kept at least 40cm from the eyes.

Allamby said people need to ensure they limit screen time whenever possible by going outside without using their phone for a portion of the day. That’s because sunlight has been shown to reduce the progression of short sightedness.

What’s more, parents should strongly consider the age at which they give their children a smartphone. He noted that children as young as seven are being given handsets which puts them at increased risk of myopia.

Do you have any children and if so, have you given them a smartphone yet? If so, at what age?