The research, published today (January 27) in the science journal Nature, shows that a gene called melanopsin causes nerve cells to become photoreceptive.
The team of experts from The University of Manchester and Imperial College London found that activating melanopsin in cells that don't normally use the gene makes them sensitive to light.
"The melanopsin made the cells photoreceptive which tells us that this protein is able to absorb light," said Dr Rob Lucas, who led the team in Manchester.
"This discovery might provide food for thought for scientists looking for ways of treating visual loss."
Dr Lucas, whose research concerns the effect light has on our daily rhythms, said the classical view of how the eye sees is through photoreceptive cells in the retina called rods and cones.
But Dr Lucas and Professor Hankins were part of a team that recently discovered a third type of photoreceptor, although the mechanisms of how it worked had not been fully understood until now.
"Over the last few years it has become increasingly accepted that we have a third system that uses melanopsin and has lain undetected during years of vigorous scientific investigation," said Dr Lucas.
"For this latest research, we introduced melanopsin to cells that do not normally use it. What we found is that the cell becomes photosensitised and is able to produce a biological signal.
"The discovery that melanopsin is capable of making cells photosensitive has given us a unique opportunity to study the characteristics of this interesting protein."
For some years scientists have been exploring ways of restoring light detection to those blind people who have lost their rods and cones.