Curing blindness is one of the hottest areas of stem cell research because eyes are unlikely to reject transplanted tissue and with an ageing population, eyesight problems are a growing trend.
The US team behind this latest trial are already developing stem cell treatments for age-related macular degeneration, a condition affecting 30 million people worldwide.
But as with any stem cell therapy, the use of cells from human embryos is controversial.
Watch How We See Part 1: Eyes to find out more about how the eye works.
