Simple mobile phone displays for people with poor vision
A couple have designed software to give phones simple, bright screen displays for people with poor vision.
Dena and Simon Marks came up with the idea after Dena's cataracts prevented her from reading the display on her mobile phone.
The pair developed an app to make phones display a large letter that relates to frequent callers.
Jane Wakefield met them at Mobile World Congress (MWC) in Barcelona.