Can stem cells treat eye disease?

Ask the doctor

Q. I heard about a breakthrough in using stem cells to treat eye diseases. What is this about?

A. You probably are referring to two studies published in March 2016 in the journal Nature. They are just the latest examples of how advances from basic research on stem cells are already entering medical practice.

The first study reported the creation of new cornea tissue. The cornea is the transparent cover at the front of the eye, through which light first travels. The research team started with stem cells and used chemical signals to coax the cells to turn into a primitive eye. The cells from the primitive cornea were then grown into sheets, and those sheets were used to replace damaged corneas in rabbits. The technique restored the rabbits' vision.

Even more exciting was the use of stem cells to treat cataracts in babies. Cataracts are cloudy areas that develop in the lens inside the eye. Many older people develop cataracts and have surgery to remove the defective lens and replace it with an artificial clear lens. However, some babies are born with cataracts. Surgery is not so successful, in part because the babies' eyes are growing, requiring multiple operations to insert ever-larger artificial lenses.

Scientists discovered the stem cells that grow the lens of the eye. First, in rabbits and monkeys, they developed surgical techniques to remove a lens but leave behind the stem cells that have the ability to grow a new lens. Then they used the technique on 12 human babies born with cataracts. The children all grew new, cataract-free lenses within three months of surgery, without complications.

Theoretically, stem cells could treat many human diseases. That won't happen overnight. But it is coming faster than many thought it would, and for only one reason: because we have invested in basic biological research.

-- Anthony Komaroff, MD
Editor in Chief, Harvard Health Letter