Another of a number of research groups here works towards repair of damaged corneas with stem cells: researchers "have used defective corneas obtained ... [to show] how human stem cells can be caused to develop into what are known as 'epithelial cells' after 16 days' culture in the laboratory and a further 6 days' culture on a cornea. It is the epithelial cells that maintain the transparency of the cornea. ... Similar experiments have been carried out on animals, but this is the first time that stem cells have been grown on damaged human corneas. It means that we have taken the first step towards being able to use stem cells to treat damaged corneas ... If we can establish a routine method for this, the availability of material for patients who need a new cornea will be essentially unlimited. Both the surgical procedures and the aftercare will also become much more simple." While this is not the first time that stem cells have been used to repair a cornea, this sort of infrastructural work that aims to reduce cost of materials and improve efficiency of a therapeutic process is nonetheless an important step along the way to making a new therapy widely available.