Medics abroad and Bridges

John McCarthy meets ophthalmologist Lucy Mathen who runs an organisation performing cataract operations in north east India and Andrew Ready who leads a team transplanting kidneys in Trinidad and Ghana. He asks them about operating in less than ideal conditions and the impact their work has on the local communities. John also talks to architectural historian and TV presenter Dan Cruickshank about his fascination with bridges and those he has visited on his travels round the world. Producer: Harry Parker.