More than 2m people in the UK risk losing their sight through treatable eye conditions, a report warns.
Regular eye tests can save people's sight, says the RNIB
The Royal National Institute for the Blind (RNIB) says 1.9m people with diabetes and 250,000 with early-stage glaucoma unknowingly risk blindness.
The RNIB's Open Your Eyes campaign aims to bring an end to preventable sight loss in the UK by 2020.
It says more than half of sight loss is avoidable and it wants the government to promote the importance of eye tests.
In addition to these figures, two million people in the UK already suffer sight problems, the charity says.
Steve Winyard, RNIB's Head of Campaigns, said: "Ignorance is quietly robbing people of their sight every day.
"Unless action is taken now thousands of people in the UK will this year needlessly lose their sight from conditions that could be treated if caught early.
"The government needs to act now as the situation is going to get much worse with the explosion in the numbers of people with diabetes and as a result of the ageing of our population."
The RNIB is calling for the government to invest in a large-scale public awareness campaign on the importance of regular eye tests, which it says can save people's sight.
Open Your Eyes cites RNIB findings that nine out of 10 people fear losing their sight above any other sense, yet one in three people have not had an eye test in the last two years.