‘Making better eyes’ explores some of the difficulties associated with making versatile high-resolution eyes, and how these problems have been overcome. Advanced eyes need to produce a well resolved image on the retina, but must also be capable of providing the brain with useable information over a huge range of light levels. Spherical aberration and chromatic aberration affects the eyes of both land and sea animals, but can be ‘fixed’, to a greater or lesser extent, by varying gradients and curvatures. There is also a diffraction limit, especially for insect eyes. How important is the size of the receptors and how can eyes be adapted to function in dim light?