Scientists hope stem cells will help the blind see again

A ray of hope.
A ray of hope.
Image: Reuters/Soe Zeya Tun
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Surgeons in London have implanted derivatives of embryonic stem cells into the retina of a patient with macular degeneration in an attempt to restore her sight and reverse the damage of a disease that affects an estimated 10% of people over the age of 65.

Doctors at Moorfields Eye Hospital in London carried out the surgery last month on a 60-year-old woman who suffers from wet macular degeneration. It’s an age-related condition in which deformed blood vessels leak fluid or blood onto the eye, robbing the patient of sight in the center of their field of vision.

Surgeons implanted healthy retinal pigment epithelium cells grown from the stem cells—which have the potential to become any cell in the body—of donated human embryos. It will take at least three months to determine whether the patient has regained her sight and how long any improvement will last. Nine more patients are scheduled to have the surgery, in a trial funded by the drug company Pfizer.

Doctors are hopeful that the treatment could prove a breakthrough for sufferers of age-related macular degeneration, the chief cause of blindness in people over 60.

It could also be adapted to treat dry macular degeneration, in which the eye’s light-sensitive cells slowly break down. Wet macular degeneration is less common—just 10% of diagnosed cases—but brings on blindness much more swiftly. It’s believed responsible for 90% of legal blindness in the US. Currently, there’s no cure for either form.

The Moorfields trial was the first of its kind in the UK and one of several experiments around the world on the use of stem cells to cure blindness.

Earlier this year, scientists in Korea injected stem-cell-derived cells into the eyes of four patients with macular degeneration, three of whom saw improvement in their vision. Trials in the US and UK have used stem cells to halt loss of vision caused by a condition known as Stargardt’s disease, with success.