At least 2.2 billion people worldwide have a near or far vision impairment.

At least one billion of these instances could have been avoided or treated easily with eyewear or cataract surgery.

The World Health Organization (WHO) has launched "WHOeyes," a free app for the public to test how well they can see things close up and at a distance.

This app will also help them learn how to safeguard their eyes.

The app assesses visual acuity, which is the most often used assessment of visual function.

It is a basic, non-invasive test used to assess if someone has a vision impairment.

WHOeyes aims to reach out to the entire population over the age of eight, encouraging people to seek out eye care.

All six UN languages (Arabic, Chinese, English, French, Russian, and Spanish) are supported in this app.