The science of sight submits to the scrutiny of the Naked Scientists this week as we look at lens replacement surgery, the genetics of degenerative eye diseases such as macular degeneration, and find out whether gene therapy and stem cells can repair the damaged retina. Ben undergoes a laser-vision correction test to discover how corneal re-shaping can be used to correct poor vision, and Meera meets a man to uncover the basis of blinking and the composition of tears. Plus, how we hear how seashells have inspired tough new ceramics, uncover a signal that links food to body fat, and hear how a fraction of a dose of vaccine may be enough to prevent an epidemic. In Kitchen Science, Ben and Dave wonder what happens to the rainbow-effect on a CD when you hold it under a street-light...