Frank will focus on the 'Lost and Found' campaign, which promotes the charity's work with those who have lost their sight, helping them to rebuild their lives.
The RNIB has briefed Frank to improve engagement with the charity among AB consumers over 55 years old. Its recent research found that this audience was more concerned about sight loss than any other group.
Frank has put together a campaign that aims to make the audience appreciate what they would miss out on if they lost their sight.
The first stage of the campaign will focus on the experience of travel. In the next couple of weeks, it will release a series of altered images of British landmarks. These photographs demonstrate how partially sighted people view the landmarks.
The agency has also persuaded fashion photographer Mario Testino to release a never-seen-before image from his private collection.
Frank will particularly target broadsheets as well as specialist travel media to widen the campaign's audience.
RNIB's media relations manager Susan Duncan said: 'Frank has run several campaigns for charities where it has delivered stand-out coverage that has helped drive both conversion and talkability.
'We are really looking forward to working with Frank on our "Lost and Found" camp-aign and achieving cut-through among our target consumers.'
Frank had to pitch for the campaign, which will run until Christmas. Agency MD Frankie Cory will head up the account. She said she hoped the campaign would 'get consumers to consider the issue of sight loss'.
Sight loss currently affects around two million people throughout the UK.
Frank already works for other charities including Cancer Research UK, Beatbullying, Rethink and Drinkaware.